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Middleby KB, Cheesman AW, Cernusak LA. Impacts of elevated temperature and vapour pressure deficit on leaf gas exchange and plant growth across six tropical rainforest tree species. THE NEW PHYTOLOGIST 2024. [PMID: 38757766 DOI: 10.1111/nph.19822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 04/30/2024] [Indexed: 05/18/2024]
Abstract
Elevated air temperature (Tair) and vapour pressure deficit (VPDair) significantly influence plant functioning, yet their relative impacts are difficult to disentangle. We examined the effects of elevated Tair (+6°C) and VPDair (+0.7 kPa) on the growth and physiology of six tropical tree species. Saplings were grown under well-watered conditions in climate-controlled glasshouses for 6 months under three treatments: (1) low Tair and low VPDair, (2) high Tair and low VPDair, and (3) high Tair and high VPDair. To assess acclimation, physiological parameters were measured at a set temperature. Warm-grown plants grown under elevated VPDair had significantly reduced stomatal conductance and increased instantaneous water use efficiency compared to plants grown under low VPDair. Photosynthetic biochemistry and thermal tolerance (Tcrit) were unaffected by VPDair, but elevated Tair caused Jmax25 to decrease and Tcrit to increase. Sapling biomass accumulation for all species responded positively to an increase in Tair, but elevated VPDair limited growth. This study shows that stomatal limitation caused by even moderate increases in VPDair can decrease productivity and growth rates in tropical species independently from Tair and has important implications for modelling the impacts of climate change on tropical forests.
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Affiliation(s)
- Kali B Middleby
- College of Science and Engineering, James Cook University, Cairns, QLD, 4878, Australia
| | - Alexander W Cheesman
- College of Science and Engineering, James Cook University, Cairns, QLD, 4878, Australia
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, QLD, 4878, Australia
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2
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Wittemann M, Mujawamariya M, Ntirugulirwa B, Uwizeye FK, Zibera E, Manzi OJL, Nsabimana D, Wallin G, Uddling J. Plasticity and implications of water-use traits in contrasting tropical tree species under climate change. PHYSIOLOGIA PLANTARUM 2024; 176:e14326. [PMID: 38708565 DOI: 10.1111/ppl.14326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 04/12/2024] [Indexed: 05/07/2024]
Abstract
Plants face a trade-off between hydraulic safety and growth, leading to a range of water-use strategies in different species. However, little is known about such strategies in tropical trees and whether different water-use traits can acclimate to warming. We studied five water-use traits in 20 tropical tree species grown at three different altitudes in Rwanda (RwandaTREE): stomatal conductance (gs), leaf minimum conductance (gmin), plant hydraulic conductance (Kplant), leaf osmotic potential (ψo) and net defoliation during drought. We also explored the links between these traits and growth and mortality data. Late successional (LS) species had low Kplant, gs and gmin and, thus, low water loss, while low ψo helped improve leaf water status during drought. Early successional (ES) species, on the contrary, used more water during both moist and dry conditions and exhibited pronounced drought defoliation. The ES strategy was associated with lower mortality and more pronounced growth enhancement at the warmer sites compared to LS species. While Kplant and gmin showed downward acclimation in warmer climates, ψo did not acclimate and gs measured at prevailing temperature did not change. Due to distinctly different water use strategies between successional groups, ES species may be better equipped for a warmer climate as long as defoliation can bridge drought periods.
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Affiliation(s)
- Maria Wittemann
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Myriam Mujawamariya
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Kigali, Rwanda
| | - Bonaventure Ntirugulirwa
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Kigali, Rwanda
- Rwanda Agriculture and Animal Resources Development Board (RAB), Kigali, Rwanda
- Rwanda Forestry Authority, Muhanga, Rwanda
| | - Felicien K Uwizeye
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Etienne Zibera
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Olivier Jean Leonce Manzi
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Integrated Polytechnic Regional College-Kitabi, Rwanda Polytechnic, Huye, Rwanda
| | - Donat Nsabimana
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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3
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Bison NN, Michaletz ST. Variation in leaf carbon economics, energy balance, and heat tolerance traits highlights differing timescales of adaptation and acclimation. THE NEW PHYTOLOGIST 2024. [PMID: 38532535 DOI: 10.1111/nph.19702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 03/06/2024] [Indexed: 03/28/2024]
Abstract
Multivariate leaf trait correlations are hypothesized to originate from natural selection on carbon economics traits that control lifetime leaf carbon gain, and energy balance traits governing leaf temperatures, physiological rates, and heat injury. However, it is unclear whether macroevolution of leaf traits primarily reflects selection for lifetime carbon gain or energy balance, and whether photosynthetic heat tolerance is coordinated along these axes. To evaluate these hypotheses, we measured carbon economics, energy balance, and photosynthetic heat tolerance traits for 177 species (157 families) in a common garden that minimizes co-variation of taxa and climate. We observed wide variation in carbon economics, energy balance, and heat tolerance traits. Carbon economics and energy balance (but not heat tolerance) traits were phylogenetically structured, suggesting macroevolution of leaf mass per area and leaf dry matter content reflects selection on carbon gain rather than energy balance. Carbon economics and energy balance traits varied along a common axis orthogonal to heat tolerance traits. Our results highlight a fundamental mismatch in the timescales over which morphological and heat tolerance traits respond to environmental variation. Whereas carbon economics and energy balance traits are constrained by species' evolutionary histories, photosynthetic heat tolerance traits are not and can acclimate readily to leaf microclimates.
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Affiliation(s)
- Nicole N Bison
- Department of Botany, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Biodiversity Research Centre, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Sean T Michaletz
- Department of Botany, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Biodiversity Research Centre, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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Song X, Gu J, Ye Y, Wang M, Wang R, Ma H, Shao X. Exploring Intraspecific Trait Variation in a Xerophytic Moss Species Indusiella thianschanica (Ptychomitriaceae) across Environmental Gradients on the Tibetan Plateau. PLANTS (BASEL, SWITZERLAND) 2024; 13:921. [PMID: 38611451 PMCID: PMC11013618 DOI: 10.3390/plants13070921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 04/14/2024]
Abstract
Investigating intraspecific trait variability is crucial for understanding plant adaptation to various environments, yet research on lithophytic mosses in extreme environments remains scarce. This study focuses on Indusiella thianschanica Broth. Hal., a unique lithophytic moss species in the extreme environments of the Tibetan Plateau, aiming to uncover its adaptation and response mechanisms to environmental changes. Specimens were collected from 26 sites across elevations ranging from 3642 m to 5528 m, and the relationships between 23 morphological traits and 15 environmental factors were analyzed. Results indicated that coefficients of variation (CV) ranged from 5.91% to 36.11%, with gametophyte height (GH) and basal cell transverse wall thickness (STW) showing the highest and lowest variations, respectively. Temperature, elevation, and potential evapo-transpiration (PET) emerged as primary environmental drivers. Leaf traits, especially those of the leaf sheath, exhibited a more pronounced response to the environment. The traits exhibited apparent covariation in response to environmental challenges and indicated flexible adaptive strategies. This study revealed the adaptation and response patterns of different morphological traits of I. thianschanica to environmental changes on the Tibetan Plateau, emphasizing the significant effect of temperature on trait variation. Our findings deepen the understanding of the ecology and adaptive strategies of lithophytic mosses.
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Affiliation(s)
- Xiaotong Song
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; (X.S.); (J.G.); (M.W.)
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Jiqi Gu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; (X.S.); (J.G.); (M.W.)
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
- State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Yanhui Ye
- Resources & Environment College, Tibet Agriculture & Animal Husbandry University, Nyingchi 860000, China;
| | - Mengzhen Wang
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; (X.S.); (J.G.); (M.W.)
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Ruihong Wang
- Institute of Tibet Plateau Ecology, Tibet Agricultural & Animal Husbandry University, Nyingchi 860000, China; (R.W.); (H.M.)
- Key Laboratory of Forest Ecology in Tibet Plateau, Tibet Agricultural & Animal Husbandry University, Ministry of Education, Nyingchi 860000, China
| | - Heping Ma
- Institute of Tibet Plateau Ecology, Tibet Agricultural & Animal Husbandry University, Nyingchi 860000, China; (R.W.); (H.M.)
- Key Laboratory of Forest Ecology in Tibet Plateau, Tibet Agricultural & Animal Husbandry University, Ministry of Education, Nyingchi 860000, China
| | - Xiaoming Shao
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; (X.S.); (J.G.); (M.W.)
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
- Resources & Environment College, Tibet Agriculture & Animal Husbandry University, Nyingchi 860000, China;
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Ning QR, Li Q, Zhang HP, Jin Y, Gong XW, Jiao RF, Bakpa EP, Zhao H, Liu H. Weak correlations among leaf thermal metrics, economic traits and damages under natural heatwaves. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:170022. [PMID: 38220006 DOI: 10.1016/j.scitotenv.2024.170022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/29/2023] [Accepted: 01/07/2024] [Indexed: 01/16/2024]
Abstract
The frequency and intensity of heatwaves are increasing around the world, causing severe damages to plants, but whether leaf thermal metrics is in line with leaf economic spectrum is still controversial. Here, we measured leaf damage ratio, leaf thermal metrics (tolerance and sensitivity) and economic traits of 131 woody species across five cities along the Yangtze River after a two-month natural extreme temperature event. We found that leaf thermal sensitivity but not thermal tolerance was correlated with leaf damage ratio, and the relationships between leaf thermal metrics and economic traits were weak, indicating that leaf thermal adaptation may be independent from leaf carbon construction. This study suggests a potential indicator for predicting plant survival under heatwaves, urging future research to explore more physiological traits to comprehensively understand plant heat responses and adaptations.
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Affiliation(s)
- Qiu-Rui Ning
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Qiang Li
- School of Tropical Medicine, Hainan Medical University, Haikou, China
| | - Hao-Ping Zhang
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Yi Jin
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China
| | - Xue-Wei Gong
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Rui-Fang Jiao
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Emily Patience Bakpa
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Han Zhao
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Hui Liu
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
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6
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Cox AJF, González-Caro S, Meir P, Hartley IP, Restrepo Z, Villegas JC, Sanchez A, Mercado LM. Variable thermal plasticity of leaf functional traits in Andean tropical montane forests. PLANT, CELL & ENVIRONMENT 2024; 47:731-750. [PMID: 38047584 DOI: 10.1111/pce.14778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 11/08/2023] [Accepted: 11/21/2023] [Indexed: 12/05/2023]
Abstract
Tropical montane forests (TMFs) are biodiversity hotspots and provide vital ecosystem services, but they are disproportionately vulnerable to climate warming. In the Andes, cold-affiliated species from high elevations are being displaced at the hot end of their thermal distributions by warm-affiliated species migrating upwards from lower elevations, leading to compositional shifts. Leaf functional traits are strong indicators of plant performance and at the community level have been shown to vary along elevation gradients, reflecting plant adaptations to different environmental niches. However, the plastic response of such traits to relatively rapid temperature change in Andean TMF species remains unknown. We used three common garden plantations within a thermosequence in the Colombian Andes to investigate the warming and cooling responses of key leaf functional traits in eight cold- and warm-affiliated species with variable thermal niches. Cold-affiliated species shifted their foliar nutrient concentrations when exposed to warming, while all other traits did not significantly change; contrastingly, warm-affiliated species were able to adjust structural, nutrient and water-use efficiency traits from acquisitive to conservative strategies in response to cooling. Our findings suggest that cold-affiliated species will struggle to acclimate functional traits to warming, conferring warm-affiliated species a competitive advantage under climate change.
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Affiliation(s)
- Andrew J F Cox
- Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Sebastián González-Caro
- Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Patrick Meir
- School of Geosciences, University of Edinburgh, Edinburgh, UK
- Division of Plant Sciences, Research, The Australian National University, Canberra, Australia
| | - Iain P Hartley
- Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Zorayda Restrepo
- Grupo de Investigación en Ecología Aplicada, Universidad de Antioquia, Medellín, Colombia
- Grupo de Servicios Ecositémicos y Cambio Climático, Corporación, Medellín, Colombia
| | - Juan C Villegas
- Grupo de Investigación en Ecología Aplicada, Universidad de Antioquia, Medellín, Colombia
| | - Adriana Sanchez
- Programa de Biología, Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Lina M Mercado
- Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
- UK Centre for Ecology & Hydrology, Crowmarsh-Gifford, Wallingford, UK
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7
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Gao T, Zhang D, Shen W, Xu S, Jia X, Liu X, Tan K, Zhou Y, Zhang Z, Ma F, Li C. MdASMT9-mediated melatonin biosynthesis enhances basal thermotolerance in apple plants. PLANT, CELL & ENVIRONMENT 2024; 47:751-764. [PMID: 38164091 DOI: 10.1111/pce.14791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 11/26/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
High temperatures negatively impact the yield and quality of fruit crops. Exogenous melatonin (MT) application has been shown to enhance heat tolerance, but the response of endogenous MT to heat stress, particularly in perennial fruit trees, remains unclear. The present study investigated the effects of high temperatures on transgenic apple plants overexpressing the MT biosynthesis gene N-acetylserotonin methyltransferase 9 (MdASMT9). Endogenous MT protected transgenic plants from heat stress by increasing antioxidant enzyme activity and scavenging reactive oxygen species (ROS), and protecting the chloroplasts from damage. Application of MT and overexpression of MdASMT9 also reduced abscisic acid accumulation through promoting MdWRKY33-mediated transcriptional inhibition of MdNCED1 and MdNCED3, thus inducing stomatal opening for better heat dissipation. Furthermore, MT-enhanced autophagic activity through promoting MdWRKY33-mediated transcriptional enhancement of MdATG18a under heat stress. These findings provide new insights into the regulation of endogenous MT and its role in improving basal thermotolerance in perennial fruit trees.
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Affiliation(s)
- Tengteng Gao
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Danni Zhang
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Wentao Shen
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Shuo Xu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Xumei Jia
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiaomin Liu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Kexin Tan
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Yi Zhou
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Zhijun Zhang
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Fengwang Ma
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Chao Li
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, Pomology Department, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
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Wei L, Sanczuk P, De Pauw K, Caron MM, Selvi F, Hedwall PO, Brunet J, Cousins SAO, Plue J, Spicher F, Gasperini C, Iacopetti G, Orczewska A, Uria-Diez J, Lenoir J, Vangansbeke P, De Frenne P. Using warming tolerances to predict understory plant responses to climate change. GLOBAL CHANGE BIOLOGY 2024; 30:e17064. [PMID: 38273565 DOI: 10.1111/gcb.17064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 10/27/2023] [Accepted: 11/06/2023] [Indexed: 01/27/2024]
Abstract
Climate change is pushing species towards and potentially beyond their critical thermal limits. The extent to which species can cope with temperatures exceeding their critical thermal limits is still uncertain. To better assess species' responses to warming, we compute the warming tolerance (ΔTniche ) as a thermal vulnerability index, using species' upper thermal limits (the temperature at the warm limit of their distribution range) minus the local habitat temperature actually experienced at a given location. This metric is useful to predict how much more warming species can tolerate before negative impacts are expected to occur. Here we set up a cross-continental transplant experiment involving five regions distributed along a latitudinal gradient across Europe (43° N-61° N). Transplant sites were located in dense and open forests stands, and at forest edges and in interiors. We estimated the warming tolerance for 12 understory plant species common in European temperate forests. During 3 years, we examined the effects of the warming tolerance of each species across all transplanted locations on local plant performance, in terms of survival, height, ground cover, flowering probabilities and flower number. We found that the warming tolerance (ΔTniche ) of the 12 studied understory species was significantly different across Europe and varied by up to 8°C. In general, ΔTniche were smaller (less positive) towards the forest edge and in open stands. Plant performance (growth and reproduction) increased with increasing ΔTniche across all 12 species. Our study demonstrated that ΔTniche of understory plant species varied with macroclimatic differences among regions across Europe, as well as in response to forest microclimates, albeit to a lesser extent. Our findings support the hypothesis that plant performance across species decreases in terms of growth and reproduction as local temperature conditions reach or exceed the warm limit of the focal species.
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Affiliation(s)
- Liping Wei
- CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Melle-Gontrode, Belgium
| | - Pieter Sanczuk
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Melle-Gontrode, Belgium
| | - Karen De Pauw
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Melle-Gontrode, Belgium
| | - Maria Mercedes Caron
- Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET, Córdoba, Argentina
- European Forest Institute-Mediterranean Facility, Barcelona, Spain
| | - Federico Selvi
- Department of Agriculture, Food, Environment and Forestry, University of Florence, Florence, Italy
| | - Per-Ola Hedwall
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Jörg Brunet
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Sara A O Cousins
- Landscapes, Environment and Geomatics, Department of Physical Geography, Stockholm University, Stockholm, Sweden
| | - Jan Plue
- Department of Urban and Rural Development, SLU Swedish Biodiversity Centre (CBM), Institutionen för stad och land, Uppsala, Sweden
| | - Fabien Spicher
- UMR CNRS 7058 Ecologie et Dynamique des Systèmes Anthropisés (EDYSAN), Université de Picardie Jules Verne, Amiens, France
| | - Cristina Gasperini
- Department of Agriculture, Food, Environment and Forestry, University of Florence, Florence, Italy
| | - Giovanni Iacopetti
- Department of Agriculture, Food, Environment and Forestry, University of Florence, Florence, Italy
| | - Anna Orczewska
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, Katowice, Poland
| | - Jaime Uria-Diez
- Department of Forest Sciences, NEIKER-Basque Institute for Agricultural Research and Development, Basque Research and Technology Alliance (BRTA), Derio, Spain
| | - Jonathan Lenoir
- UMR CNRS 7058 Ecologie et Dynamique des Systèmes Anthropisés (EDYSAN), Université de Picardie Jules Verne, Amiens, France
| | - Pieter Vangansbeke
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Melle-Gontrode, Belgium
- Earth and Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Pieter De Frenne
- Forest & Nature Lab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Melle-Gontrode, Belgium
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9
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Qu LP, Chen J, Xiao J, De Boeck HJ, Dong G, Jiang SC, Hu YL, Wang YX, Shao CL. The complexity of heatwaves impact on terrestrial ecosystem carbon fluxes: Factors, mechanisms and a multi-stage analytical approach. ENVIRONMENTAL RESEARCH 2024; 240:117495. [PMID: 37890820 DOI: 10.1016/j.envres.2023.117495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/23/2023] [Accepted: 10/23/2023] [Indexed: 10/29/2023]
Abstract
Extreme heatwaves have become more frequent and severe in recent decades, and are expected to significantly influence carbon fluxes at regional scales across global terrestrial ecosystems. Nevertheless, accurate prediction of future heatwave impacts remains challenging due to a lack of a consistent comprehension of intrinsic and extrinsic mechanisms. We approached this knowledge gap by analyzing the complexity factors in heatwave studies, including the methodology for determining heatwave events, divergent responses of individual ecosystem components at multiple ecological and temporal scales, and vegetation status and hydrothermal environment, among other factors. We found that heatwaves essentially are continuously changing compound environmental stress that can unfold into multiple chronological stages, and plant physiology and carbon flux responses differs in each of these stages. This approach offers a holistic perspective, recognizing that the impacts of heatwaves on ecosystems can be better understood when evaluated over time. These stages include instantaneous, post-heatwave, legacy, and cumulative effects, each contributing uniquely to the overall impact on the ecosystem carbon cycle. Next, we investigated the importance of the timing of heatwaves and the possible divergent consequences caused by different annual heatwave patterns. Finally, a conceptual framework is proposed to establish a united foundation for the study and comprehension of the consequences of heatwaves on ecosystem carbon cycle. This instrumental framework will assist in guiding regional assessments of heatwave impacts, shedding light on the underlying mechanisms responsible for the varied responses of terrestrial ecosystems to specific heatwave events, which are imperative for devising efficient adaptation and mitigation approaches.
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Affiliation(s)
- Lu-Ping Qu
- College of JunCao Science and Ecology, Fujian Agriculture and Forestry University, Fuzhou, China.
| | - Jiquan Chen
- Center for Global Change & Earth Observations (CGCEO), Michigan State University, East Lansing, MI, 48823, USA.
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, 03824, USA.
| | - Hans J De Boeck
- Research Group of Plants and Ecosystems (PLECO), Department of Biology, University of Antwerp, 2610, Wilrijk, Belgium.
| | - Gang Dong
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, National Hulunber Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China; School of Life Science, Shanxi University, Taiyuan, China.
| | | | - Ya-Lin Hu
- College of JunCao Science and Ecology, Fujian Agriculture and Forestry University, Fuzhou, China.
| | - Yi-Xuan Wang
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, National Hulunber Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
| | - Chang-Liang Shao
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, National Hulunber Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
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10
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Chen X, Li J, Peñuelas J, Li X, Hu D, Wang M, Zhong Q, Cheng D. Temperature dependence of carbon metabolism in the leaves in sun and shade in a subtropical forest. Oecologia 2024; 204:59-69. [PMID: 38091103 DOI: 10.1007/s00442-023-05487-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 11/15/2023] [Indexed: 02/02/2024]
Abstract
Rising temperatures pose a threat to the stability of climate regulation by carbon metabolism in subtropical forests. Although the effects of temperature on leaf carbon metabolism traits in sun-exposed leaves are well understood, there is limited knowledge about its impacts on shade leaves and the implications for ecosystem-climate feedbacks. In this study, we measured temperature response curves of photosynthesis and respiration for 62 woody species in summer (including both evergreen and deciduous species) and 20 evergreen species in winter. The aim was to uncover the temperature dependence of carbon metabolism in both sun and shade leaves in subtropical forests. Our findings reveal that shade had no significant effects on the mean optimum photosynthetic temperatures (TOpt) or temperature range (T90). However, there were decreases observed in mean stomatal conductance, mean area-based photosynthetic rates at TOpt and 25 °C, as well as mean area-based dark respiration rates at 25 °C in both evergreen and deciduous species. Moreover, the respiration-temperature sensitivity (Q10) of sun leaves was higher than that of shade leaves in winter, with the reverse being true in summer. Leaf economics spectrum traits, such as leaf mass per area, and leaf concentration of nitrogen and phosphorus across species, proved to be good predictors of TOpt, T90, mass-based photosynthetic rate at TOpt, and mass-based photosynthetic and respiration rate at 25 °C. However, Q10 was poorly predicted by these leaf economics spectrum traits except for shade leaves in winter. Our results suggest that model estimates of carbon metabolism in multilayered subtropical forest canopies do not necessitate independent parameterization of T90 and TOpt temperature responses in sun and shade leaves. Nevertheless, a deeper understanding and quantification of canopy variations in Q10 responses to temperature are necessary to confirm the generality of temperature-carbon metabolism trait responses and enhance ecosystem model estimates of carbon dynamics under future climate warming.
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Affiliation(s)
- Xiaoping Chen
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- College of Tourism, Resources and Environment, Zaozhuang University, Zaozhuang, Shandong, China
- Fujian Provincial Key Laboratory of Plant Ecophysiology, College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Jinlong Li
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- Fujian Provincial Key Laboratory of Plant Ecophysiology, College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Josep Peñuelas
- Global Ecology Unit, CSIC, CREAF-CSIC-UAB, 08193, Bellaterra, Catalonia, Spain
- CREAF, 08193, Cerdanyola del Vallès, Catalonia, Spain
| | - Xueqin Li
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- Fujian Provincial Key Laboratory of Plant Ecophysiology, College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Dandan Hu
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- Fujian Provincial Key Laboratory of Plant Ecophysiology, College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Mantang Wang
- College of Tourism, Resources and Environment, Zaozhuang University, Zaozhuang, Shandong, China
| | - Quanlin Zhong
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- Fujian Provincial Key Laboratory of Plant Ecophysiology, College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Dongliang Cheng
- Key Laboratory of Humid Subtropical Eco-Geographical Process (Ministry of Education), College of Geographical Sciences, Fujian Normal University, Fuzhou, China.
- Fujian Provincial Key Laboratory of Plant Ecophysiology, College of Geographical Sciences, Fujian Normal University, Fuzhou, China.
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11
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Moran ME, Aparecido LMT, Koepke DF, Cooper HF, Doughty CE, Gehring CA, Throop HL, Whitham TG, Allan GJ, Hultine KR. Limits of thermal and hydrological tolerance in a foundation tree species (Populus fremontii) in the desert southwestern United States. THE NEW PHYTOLOGIST 2023; 240:2298-2311. [PMID: 37680030 DOI: 10.1111/nph.19247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/05/2023] [Indexed: 09/09/2023]
Abstract
Populus fremontii is among the most dominant, and ecologically important riparian tree species in the western United States and can thrive in hyper-arid riparian corridors. Yet, P. fremontii forests have rapidly declined over the last decade, particularly in places where temperatures sometimes exceed 50°C. We evaluated high temperature tolerance of leaf metabolism, leaf thermoregulation, and leaf hydraulic function in eight P. fremontii populations spanning a 5.3°C mean annual temperature gradient in a well-watered common garden, and at source locations throughout the lower Colorado River Basin. Two major results emerged. First, despite having an exceptionally high Tcrit (the temperature at which Photosystem II is disrupted) relative to other tree taxa, recent heat waves exceeded Tcrit , requiring evaporative leaf cooling to maintain leaf-to-air thermal safety margins. Second, in midsummer, genotypes from the warmest locations maintained lower midday leaf temperatures, a higher midday stomatal conductance, and maintained turgor pressure at lower water potentials than genotypes from more temperate locations. Taken together, results suggest that under well-watered conditions, P. fremontii can regulate leaf temperature below Tcrit along the warm edge of its distribution. Nevertheless, reduced Colorado River flows threaten to lower water tables below levels needed for evaporative cooling during episodic heat waves.
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Affiliation(s)
- Madeline E Moran
- School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Luiza M T Aparecido
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Dan F Koepke
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
| | - Hillary F Cooper
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Christopher E Doughty
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Catherine A Gehring
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Heather L Throop
- School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Thomas G Whitham
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Gerard J Allan
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
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12
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Gauthey A, Bachofen C, Deluigi J, Didion-Gency M, D'Odorico P, Gisler J, Mas E, Schaub M, Schuler P, Still CJ, Tunas A, Grossiord C. Absence of canopy temperature variation despite stomatal adjustment in Pinus sylvestris under multidecadal soil moisture manipulation. THE NEW PHYTOLOGIST 2023; 240:127-137. [PMID: 37483100 DOI: 10.1111/nph.19136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/23/2023] [Indexed: 07/25/2023]
Abstract
Global warming and droughts push forests closer to their thermal limits, altering tree carbon uptake and growth. To prevent critical overheating, trees can adjust their thermotolerance (Tcrit ), temperature and photosynthetic optima (Topt and Aopt ), and canopy temperature (Tcan ) to stay below damaging thresholds. However, we lack an understanding of how soil droughts affect photosynthetic thermal plasticity and Tcan regulation. In this study, we measured the effect of soil moisture on the seasonal and diurnal dynamics of net photosynthesis (A), stomatal conductance (gs ), and Tcan , as well as the thermal plasticity of photosynthesis (Tcrit , Topt , and Aopt ), over the course of 1 yr using a long-term irrigation experiment in a drought-prone Pinus sylvestris forest in Switzerland. Irrigation resulted in higher needle-level A, gs , Topt , and Aopt compared with naturally drought-exposed trees. No daily or seasonal differences in Tcan were observed between treatments. Trees operated below their thermal thresholds (Tcrit ), independently of soil moisture content. Despite strong Tcan and Tair coupling, we provide evidence that drought reduces trees' temperature optimum due to a substantial reduction of gs during warm and dry periods of the year. These findings provide important insights regarding the effects of soil drought on the thermal tolerance of P. sylvestris.
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Affiliation(s)
- Alice Gauthey
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Christoph Bachofen
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Janisse Deluigi
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Margaux Didion-Gency
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Petra D'Odorico
- Land Change Science Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Jonas Gisler
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Eugénie Mas
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Marcus Schaub
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Philipp Schuler
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Christopher J Still
- Forest Ecosystems and Society, Oregon State University, Corvallis, 97331, OR, USA
| | - Alex Tunas
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
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13
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Doughty CE, Keany JM, Wiebe BC, Rey-Sanchez C, Carter KR, Middleby KB, Cheesman AW, Goulden ML, da Rocha HR, Miller SD, Malhi Y, Fauset S, Gloor E, Slot M, Oliveras Menor I, Crous KY, Goldsmith GR, Fisher JB. Tropical forests are approaching critical temperature thresholds. Nature 2023; 621:105-111. [PMID: 37612501 DOI: 10.1038/s41586-023-06391-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 06/30/2023] [Indexed: 08/25/2023]
Abstract
The critical temperature beyond which photosynthetic machinery in tropical trees begins to fail averages approximately 46.7 °C (Tcrit)1. However, it remains unclear whether leaf temperatures experienced by tropical vegetation approach this threshold or soon will under climate change. Here we found that pantropical canopy temperatures independently triangulated from individual leaf thermocouples, pyrgeometers and remote sensing (ECOSTRESS) have midday peak temperatures of approximately 34 °C during dry periods, with a long high-temperature tail that can exceed 40 °C. Leaf thermocouple data from multiple sites across the tropics suggest that even within pixels of moderate temperatures, upper canopy leaves exceed Tcrit 0.01% of the time. Furthermore, upper canopy leaf warming experiments (+2, 3 and 4 °C in Brazil, Puerto Rico and Australia, respectively) increased leaf temperatures non-linearly, with peak leaf temperatures exceeding Tcrit 1.3% of the time (11% for more than 43.5 °C, and 0.3% for more than 49.9 °C). Using an empirical model incorporating these dynamics (validated with warming experiment data), we found that tropical forests can withstand up to a 3.9 ± 0.5 °C increase in air temperatures before a potential tipping point in metabolic function, but remaining uncertainty in the plasticity and range of Tcrit in tropical trees and the effect of leaf death on tree death could drastically change this prediction. The 4.0 °C estimate is within the 'worst-case scenario' (representative concentration pathway (RCP) 8.5) of climate change predictions2 for tropical forests and therefore it is still within our power to decide (for example, by not taking the RCP 6.0 or 8.5 route) the fate of these critical realms of carbon, water and biodiversity3,4.
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Affiliation(s)
- Christopher E Doughty
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA.
| | - Jenna M Keany
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Benjamin C Wiebe
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Camilo Rey-Sanchez
- Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC, USA
| | - Kelsey R Carter
- College of Forest Resources and Environmental Sciences, Michigan Technological University, Houghton, MI, USA
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Kali B Middleby
- Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Queensland, Australia
| | - Alexander W Cheesman
- Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Queensland, Australia
| | - Michael L Goulden
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - Humberto R da Rocha
- Departamento de Ciencias Atmosfericas, Universidade de São Paulo, São Paulo, Brazil
| | - Scott D Miller
- Atmospheric Sciences Research Center, State University of New York at Albany, Albany, NY, USA
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Sophie Fauset
- School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK
| | | | - Martijn Slot
- Smithsonian Tropical Research Institute, Balboa, Ancon, Republic of Panama
| | - Imma Oliveras Menor
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
- AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), CIRAD, CNRS, INRA, IRD, Université de Montpellier, Montpellier, France
| | - Kristine Y Crous
- Western Sydney University, Hawkesbury Institute for the Environment, Penrith, New South Wales, Australia
| | - Gregory R Goldsmith
- Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Joshua B Fisher
- Schmid College of Science and Technology, Chapman University, Orange, CA, USA
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14
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Crous KY, Cheesman AW, Middleby K, Rogers EIE, Wujeska-Klause A, Bouet AYM, Ellsworth DS, Liddell MJ, Cernusak LA, Barton CVM. Similar patterns of leaf temperatures and thermal acclimation to warming in temperate and tropical tree canopies. TREE PHYSIOLOGY 2023; 43:1383-1399. [PMID: 37099805 PMCID: PMC10423462 DOI: 10.1093/treephys/tpad054] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/22/2023] [Accepted: 04/17/2023] [Indexed: 06/19/2023]
Abstract
As the global climate warms, a key question is how increased leaf temperatures will affect tree physiology and the coupling between leaf and air temperatures in forests. To explore the impact of increasing temperatures on plant performance in open air, we warmed leaves in the canopy of two mature evergreen forests, a temperate Eucalyptus woodland and a tropical rainforest. The leaf heaters consistently maintained leaves at a target of 4 °C above ambient leaf temperatures. Ambient leaf temperatures (Tleaf) were mostly coupled to air temperatures (Tair), but at times, leaves could be 8-10 °C warmer than ambient air temperatures, especially in full sun. At both sites, Tleaf was warmer at higher air temperatures (Tair > 25 °C), but was cooler at lower Tair, contrary to the 'leaf homeothermy hypothesis'. Warmed leaves showed significantly lower stomatal conductance (-0.05 mol m-2 s-1 or -43% across species) and net photosynthesis (-3.91 μmol m-2 s-1 or -39%), with similar rates in leaf respiration rates at a common temperature (no acclimation). Increased canopy leaf temperatures due to future warming could reduce carbon assimilation via reduced photosynthesis in these forests, potentially weakening the land carbon sink in tropical and temperate forests.
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Affiliation(s)
- K Y Crous
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - A W Cheesman
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - K Middleby
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - E I E Rogers
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - A Wujeska-Klause
- Urban Studies, School of Social Science, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - A Y M Bouet
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - D S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - M J Liddell
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - L A Cernusak
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - C V M Barton
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
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15
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Cox AJF, Hartley IP, Meir P, Sitch S, Dusenge ME, Restrepo Z, González-Caro S, Villegas JC, Uddling J, Mercado LM. Acclimation of photosynthetic capacity and foliar respiration in Andean tree species to temperature change. THE NEW PHYTOLOGIST 2023; 238:2329-2344. [PMID: 36987979 DOI: 10.1111/nph.18900] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/13/2023] [Indexed: 05/19/2023]
Abstract
Climate warming is causing compositional changes in Andean tropical montane forests (TMFs). These shifts are hypothesised to result from differential responses to warming of cold- and warm-affiliated species, with the former experiencing mortality and the latter migrating upslope. The thermal acclimation potential of Andean TMFs remains unknown. Along a 2000 m Andean altitudinal gradient, we planted individuals of cold- and warm-affiliated species (under common soil and irrigation), exposing them to the hot and cold extremes of their thermal niches, respectively. We measured the response of net photosynthesis (Anet ), photosynthetic capacity and leaf dark respiration (Rdark ) to warming/cooling, 5 months after planting. In all species, Anet and photosynthetic capacity at 25°C were highest when growing at growth temperatures (Tg ) closest to their thermal means, declining with warming and cooling in cold-affiliated and warm-affiliated species, respectively. When expressed at Tg , photosynthetic capacity and Rdark remained unchanged in cold-affiliated species, but the latter decreased in warm-affiliated counterparts. Rdark at 25°C increased with temperature in all species, but remained unchanged when expressed at Tg . Both species groups acclimated to temperature, but only warm-affiliated species decreased Rdark to photosynthetic capacity ratio at Tg as temperature increased. This could confer them a competitive advantage under future warming.
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Affiliation(s)
- Andrew J F Cox
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
| | - Iain P Hartley
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
| | - Patrick Meir
- School of Geosciences, University of Edinburgh, Edinburgh, EH9 3JN, UK
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Stephen Sitch
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
| | - Mirindi Eric Dusenge
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, The University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Zorayda Restrepo
- Grupo de Investigación en Ecología Aplicada, Universidad de Antioquia, Medellín, Colombia
- UK Centre for Ecology and Hydrology, Crowmarsh-Gifford, Wallingford, OX10 8BB, UK
| | - Sebastian González-Caro
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
- UK Centre for Ecology and Hydrology, Crowmarsh-Gifford, Wallingford, OX10 8BB, UK
| | - Juan Camilo Villegas
- Grupo de Investigación en Ecología Aplicada, Universidad de Antioquia, Medellín, Colombia
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Lina M Mercado
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
- UK Centre for Ecology and Hydrology, Crowmarsh-Gifford, Wallingford, OX10 8BB, UK
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16
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Guo Z, Still CJ, Lee CKF, Ryu Y, Blonder B, Wang J, Bonebrake TC, Hughes A, Li Y, Yeung HCH, Zhang K, Law YK, Lin Z, Wu J. Does plant ecosystem thermoregulation occur? An extratropical assessment at different spatial and temporal scales. THE NEW PHYTOLOGIST 2023; 238:1004-1018. [PMID: 36495263 DOI: 10.1111/nph.18632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/11/2022] [Indexed: 06/17/2023]
Abstract
To what degree plant ecosystems thermoregulate their canopy temperature (Tc ) is critical to assess ecosystems' metabolisms and resilience with climate change, but remains controversial, with opinions from no to moderate thermoregulation capability. With global datasets of Tc , air temperature (Ta ), and other environmental and biotic variables from FLUXNET and satellites, we tested the 'limited homeothermy' hypothesis (indicated by Tc & Ta regression slope < 1 or Tc < Ta around midday) across global extratropics, including temporal and spatial dimensions. Across daily to weekly and monthly timescales, over 80% of sites/ecosystems have slopes ≥1 or Tc > Ta around midday, rejecting the above hypothesis. For those sites unsupporting the hypothesis, their Tc -Ta difference (ΔT) exhibits considerable seasonality that shows negative, partial correlations with leaf area index, implying a certain degree of thermoregulation capability. Spatially, site-mean ΔT exhibits larger variations than the slope indicator, suggesting ΔT is a more sensitive indicator for detecting thermoregulatory differences across biomes. Furthermore, this large spatial-wide ΔT variation (0-6°C) is primarily explained by environmental variables (38%) and secondarily by biotic factors (15%). These results demonstrate diverse thermoregulation patterns across global extratropics, with most ecosystems negating the 'limited homeothermy' hypothesis, but their thermoregulation still occurs, implying that slope < 1 or Tc < Ta are not necessary conditions for plant thermoregulation.
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Affiliation(s)
- Zhengfei Guo
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Christopher J Still
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Calvin K F Lee
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Youngryel Ryu
- Department of Landscape Architecture and Rural Systems Engineering, College of Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul, South Korea
| | - Benjamin Blonder
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
| | - Jing Wang
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Timothy C Bonebrake
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China
| | - Alice Hughes
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China
| | - Yan Li
- State Key Laboratory of Earth Surface Processes and Resources Ecology, Beijing Normal University, Beijing, 100875, China
| | - Henry C H Yeung
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Kun Zhang
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Mathematics, The University of Hong Kong, Hong Kong, China
| | - Ying Ki Law
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Ziyu Lin
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Jin Wu
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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17
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Vinod N, Slot M, McGregor IR, Ordway EM, Smith MN, Taylor TC, Sack L, Buckley TN, Anderson-Teixeira KJ. Thermal sensitivity across forest vertical profiles: patterns, mechanisms, and ecological implications. THE NEW PHYTOLOGIST 2023; 237:22-47. [PMID: 36239086 DOI: 10.1111/nph.18539] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 07/31/2022] [Indexed: 06/16/2023]
Abstract
Rising temperatures are influencing forests on many scales, with potentially strong variation vertically across forest strata. Using published research and new analyses, we evaluate how microclimate and leaf temperatures, traits, and gas exchange vary vertically in forests, shaping tree, and ecosystem ecology. In closed-canopy forests, upper canopy leaves are exposed to the highest solar radiation and evaporative demand, which can elevate leaf temperature (Tleaf ), particularly when transpirational cooling is curtailed by limited stomatal conductance. However, foliar traits also vary across height or light gradients, partially mitigating and protecting against the elevation of upper canopy Tleaf . Leaf metabolism generally increases with height across the vertical gradient, yet differences in thermal sensitivity across the gradient appear modest. Scaling from leaves to trees, canopy trees have higher absolute metabolic capacity and growth, yet are more vulnerable to drought and damaging Tleaf than their smaller counterparts, particularly under climate change. By contrast, understory trees experience fewer extreme high Tleaf 's but have fewer cooling mechanisms and thus may be strongly impacted by warming under some conditions, particularly when exposed to a harsher microenvironment through canopy disturbance. As the climate changes, integrating the patterns and mechanisms reviewed here into models will be critical to forecasting forest-climate feedback.
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Affiliation(s)
- Nidhi Vinod
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, 22630, USA
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, 90039, USA
| | - Martijn Slot
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama City, Panama
| | - Ian R McGregor
- Center for Geospatial Analytics, North Carolina State University, Raleigh, NC, 27607, USA
| | - Elsa M Ordway
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, 90039, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Marielle N Smith
- Department of Forestry, Michigan State University, East Lansing, MI, 48824, USA
- School of Natural Sciences, College of Environmental Sciences and Engineering, Bangor University, Bangor, LL57 2DG, UK
| | - Tyeen C Taylor
- Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, 90039, USA
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Kristina J Anderson-Teixeira
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, 22630, USA
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama City, Panama
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18
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Docherty EM, Gloor E, Sponchiado D, Gilpin M, Pinto CAD, Junior HM, Coughlin I, Ferreira L, Junior JAS, da Costa ACL, Meir P, Galbraith D. Long-term drought effects on the thermal sensitivity of Amazon forest trees. PLANT, CELL & ENVIRONMENT 2023; 46:185-198. [PMID: 36230004 PMCID: PMC10092618 DOI: 10.1111/pce.14465] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/07/2022] [Accepted: 10/09/2022] [Indexed: 06/16/2023]
Abstract
The continued functioning of tropical forests under climate change depends on their resilience to drought and heat. However, there is little understanding of how tropical forests will respond to combinations of these stresses, and no field studies to date have explicitly evaluated whether sustained drought alters sensitivity to temperature. We measured the temperature response of net photosynthesis, foliar respiration and the maximum quantum efficiency of photosystem II (Fv /Fm ) of eight hyper-dominant Amazonian tree species at the world's longest-running tropical forest drought experiment, to investigate the effect of drought on forest thermal sensitivity. Despite a 0.6°C-2°C increase in canopy air temperatures following long-term drought, no change in overall thermal sensitivity of net photosynthesis or respiration was observed. However, photosystem II tolerance to extreme-heat damage (T50 ) was reduced from 50.0 ± 0.3°C to 48.5 ± 0.3°C under drought. Our results suggest that long-term reductions in precipitation, as projected across much of Amazonia by climate models, are unlikely to greatly alter the response of tropical forests to rising mean temperatures but may increase the risk of leaf thermal damage during heatwaves.
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Affiliation(s)
- Emma M. Docherty
- Department of Earth and Environment, School of GeographyUniversity of LeedsLeedsUK
| | - Emanuel Gloor
- Department of Earth and Environment, School of GeographyUniversity of LeedsLeedsUK
| | - Daniela Sponchiado
- Departamento de Ciências Biológicas, Laboratório de Ecologia VegetalUniversidade do Estado de Mato GrossoNova XavantinaMato GrossoBrasil
| | - Martin Gilpin
- Department of Earth and Environment, School of GeographyUniversity of LeedsLeedsUK
| | | | | | - Ingrid Coughlin
- Departamento de Biologia, FFCLRPUniversidade de São PauloRibeirao PretoSão PauloBrasil
- College of Science, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritorAustralia
| | | | | | - Antonio C. L. da Costa
- Instituto de GeosciênciasUniversidade Federaldo ParáBelémParáBrasil
- Museu Paraense Emílio GoeldiBelémParáBrasil
| | - Patrick Meir
- College of Science, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritorAustralia
- College of Science and Engineering, School of GeoSciencesUniversity of EdinburghEdinburghUK
| | - David Galbraith
- Department of Earth and Environment, School of GeographyUniversity of LeedsLeedsUK
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19
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Tree species matter for forest microclimate regulation during the drought year 2018: disentangling environmental drivers and biotic drivers. Sci Rep 2022; 12:17559. [PMID: 36266469 PMCID: PMC9584904 DOI: 10.1038/s41598-022-22582-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 10/17/2022] [Indexed: 01/13/2023] Open
Abstract
Tree canopies are considered to effectively buffer climate extremes and to mitigate climate change effects. Droughts, which are predicted to become more frequent in the course of climate change, might alter the microclimatic cooling potential of trees. However, our understanding of how microclimate at the tree canopy level is modulated by environmental and tree characteristics and their interactions is still limited. Here, we investigated canopy temperature regulation for five mature co-occurring tree species for two contrasting hydrological situations during the severe drought in 2018. Even though we observed a significant drought-induced decline in canopy cover and transpiration across tree species, we found evidence that differences in the water use strategies of trees affected cooling mechanisms differently. Although a large share of the variations in the cooling potential of trees was explained by direct and indirect effects of meteorological factors, we identified a gradual shift in importance from latent heat flux to components defining the magnitude of sensible heat flux on the energy budget of tree as the drought gained severity. The decrease in latent heat fluxes, approximated by sap flow rates, furthermore resulted in a reduced cooling potential and an equalization of tree species canopy temperatures.
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20
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Li X, Wen Y, Chen X, Qie Y, Cao KF, Wee AKS. Correlations between photosynthetic heat tolerance and leaf anatomy and climatic niche in Asian mangrove trees. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:960-966. [PMID: 35962602 DOI: 10.1111/plb.13460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
Photosynthetic heat tolerance (PHT ) is a key predictor of plant response to climate change. Mangroves are an ecologically and economically important coastal plant community comprised of trees growing at their physiological limits. Mangroves are currently impacted by global warming, yet the PHT of mangrove trees is poorly understood. In this study, we provide the first assessment of PHT in 13 Asian mangrove species, based on the critical temperature that causes the initial damage (TCrit ) and the temperature that causes 50% damage (T50 ) to photosystem II. We tested the hypotheses that the PHT in mangroves is: (i) correlated with climatic niche and leaf traits, and (ii) higher than in plants from other tropical ecosystems. Our results demonstrated correlations between PHT and multiple key climate variables, the palisade to spongy mesophyll ratio and the leaf area. The two most heat-sensitive species were Kandelia obovata and Avicennia marina. Our study also revealed that mangrove trees show high heat tolerance compared to plants from other tropical ecosystems. The high PHT of mangroves thus demonstrated a conservative evolutionary strategy in heat tolerance, and highlights the need for integrative and comparative studies on thermoregulatory traits and climatic niche in order to understand the physiological response of mangrove trees to climate change-driven heatwaves and rising global temperatures.
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Affiliation(s)
- X Li
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - Y Wen
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - X Chen
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - Y Qie
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - K-F Cao
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - A K S Wee
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
- School of Environmental and Geographical Sciences, University of Nottingham Malaysia, Jalan Broga, Semenyih, Malaysia
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21
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No evidence of canopy-scale leaf thermoregulation to cool leaves below air temperature across a range of forest ecosystems. Proc Natl Acad Sci U S A 2022; 119:e2205682119. [PMID: 36095211 PMCID: PMC9499539 DOI: 10.1073/pnas.2205682119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding and predicting the relationship between leaf temperature (Tleaf) and air temperature (Tair) is essential for projecting responses to a warming climate, as studies suggest that many forests are near thermal thresholds for carbon uptake. Based on leaf measurements, the limited leaf homeothermy hypothesis argues that daytime Tleaf is maintained near photosynthetic temperature optima and below damaging temperature thresholds. Specifically, leaves should cool below Tair at higher temperatures (i.e., > ∼25-30°C) leading to slopes <1 in Tleaf/Tair relationships and substantial carbon uptake when leaves are cooler than air. This hypothesis implies that climate warming will be mitigated by a compensatory leaf cooling response. A key uncertainty is understanding whether such thermoregulatory behavior occurs in natural forest canopies. We present an unprecedented set of growing season canopy-level leaf temperature (Tcan) data measured with thermal imaging at multiple well-instrumented forest sites in North and Central America. Our data do not support the limited homeothermy hypothesis: canopy leaves are warmer than air during most of the day and only cool below air in mid to late afternoon, leading to Tcan/Tair slopes >1 and hysteretic behavior. We find that the majority of ecosystem photosynthesis occurs when canopy leaves are warmer than air. Using energy balance and physiological modeling, we show that key leaf traits influence leaf-air coupling and ultimately the Tcan/Tair relationship. Canopy structure also plays an important role in Tcan dynamics. Future climate warming is likely to lead to even greater Tcan, with attendant impacts on forest carbon cycling and mortality risk.
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22
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Carter KR, Dickman LT. Recovery of seedling carbon balance despite hydraulic impairment following hot drought. TREE PHYSIOLOGY 2022; 42:1527-1531. [PMID: 35445728 DOI: 10.1093/treephys/tpac045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/04/2022] [Indexed: 06/14/2023]
Affiliation(s)
- Kelsey R Carter
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - L Turin Dickman
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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23
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Brienen R, Helle G, Pons T, Boom A, Gloor M, Groenendijk P, Clerici S, Leng M, Jones C. Paired analysis of tree ring width and carbon isotopes indicates when controls on tropical tree growth change from light to water limitations. TREE PHYSIOLOGY 2022; 42:1131-1148. [PMID: 34718816 PMCID: PMC9190751 DOI: 10.1093/treephys/tpab142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Light and water availability are likely to vary over the lifespan of closed-canopy forest trees, with understory trees experiencing greater limitations to growth by light and canopy trees greater limitation due to drought. As drought and shade have opposing effects on isotope discrimination (Δ13C), paired measurement of ring width and Δ13C can potentially be used to differentiate between water and light limitations on tree growth. We tested this approach for Cedrela trees from three tropical forests in Bolivia and Mexico that differ in rainfall and canopy structure. Using lifetime ring width and Δ13C data for trees of up to and over 200 years old, we assessed how controls on tree growth changed from understory to the canopy. Growth and Δ13C are mostly anti-correlated in the understory, but this anti-correlation disappeared or weakened when trees reached the canopy, especially at the wettest site. This indicates that understory growth variation is controlled by photosynthetic carbon assimilation due to variation in light levels. Once trees reached the canopy, inter-annual variation in growth and Δ13C at one of the dry sites showed positive correlations, indicating that inter-annual variation in growth is driven by variation in water stress affecting stomatal conductance. Paired analysis of ring widths and carbon isotopes provides significant insight in what environmental factors control growth over a tree's life; strong light limitations for understory trees in closed-canopy moist forests switched to drought stress for (sub)canopy trees in dry forests. We show that combined isotope and ring width measurements can significantly improve our insights in tree functioning and be used to disentangle limitations due to shade from those due to drought.
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Affiliation(s)
| | - Gerhard Helle
- GFZ—German Research Centre for Geosciences, Section 4.3 Climate Dynamics and Landscape Evolution, 14473 Potsdam, Germany
| | - Thijs Pons
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3512 Utrecht, The Netherlands
| | - Arnoud Boom
- School of Geography, University of Leicester, Leicester LE1 7RH, UK
| | - Manuel Gloor
- School of Geography, University of Leeds, Leeds LS2 9JT, UK
| | - Peter Groenendijk
- Department of Plant Biology, Institute of Biology, PO Box: 6109, University of Campinas, UNICAMP, Campinas 13083-970, Brazil
- Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, 3584 Utrecht, The Netherlands
| | | | - Melanie Leng
- National Environmental Isotope Facility, British Geological Survey, Nottingham NG12 5GG, UK
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24
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Blasini DE, Koepke DF, Bush SE, Allan GJ, Gehring CA, Whitham TG, Day TA, Hultine KR. Tradeoffs between leaf cooling and hydraulic safety in a dominant arid land riparian tree species. PLANT, CELL & ENVIRONMENT 2022; 45:1664-1681. [PMID: 35147232 DOI: 10.1111/pce.14292] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Leaf carbon gain optimization in hot environments requires balancing leaf thermoregulation with avoiding excessive water loss via transpiration and hydraulic failure. The tradeoffs between leaf thermoregulation and transpirational water loss can determine the ecological consequences of heat waves that are increasing in frequency and intensity. We evaluated leaf thermoregulation strategies in warm- (>40°C maximum summer temperature) and cool-adapted (<40°C maximum summer temperature) genotypes of the foundation tree species, Populus fremontii, using a common garden near the mid-elevational point of its distribution. We measured leaf temperatures and assessed three modes of leaf thermoregulation: leaf morphology, midday canopy stomatal conductance and stomatal sensitivity to vapour pressure deficit. Data were used to parameterize a leaf energy balance model to estimate contrasts in midday leaf temperature in warm- and cool-adapted genotypes. Warm-adapted genotypes had 39% smaller leaves and 38% higher midday stomatal conductance, reflecting a 3.8°C cooler mean leaf temperature than cool-adapted genotypes. Leaf temperatures modelled over the warmest months were on average 1.1°C cooler in warm- relative to cool-adapted genotypes. Results show that plants adapted to warm environments are predisposed to tightly regulate leaf temperatures during heat waves, potentially at an increased risk of hydraulic failure.
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Affiliation(s)
- Davis E Blasini
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Dan F Koepke
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, Arizona, USA
| | - Susan E Bush
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, Arizona, USA
| | - Gerard J Allan
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Catherine A Gehring
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Thomas G Whitham
- Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Thomas A Day
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, Arizona, USA
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25
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Bartholomew DC, Banin LF, Bittencourt PRL, Suis MAF, Mercado LM, Nilus R, Burslem DFRP, Rowland LR. Differential nutrient limitation and tree height control leaf physiology, supporting niche partitioning in tropical dipterocarp forests. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- D. C. Bartholomew
- College of Life and Environmental Sciences University of Exeter Exeter UK
- Department of Ecology and Environmental Science Umeå University Umeå Sweden
| | - L. F. Banin
- UK Centre for Ecology & Hydrology, Penicuik Midlothian UK
| | | | - M. A. F. Suis
- Forest Research Centre, Sabah Forestry Department, P.O. Box 1407, 90715 Sandakan Sabah Malaysia
| | - L. M. Mercado
- College of Life and Environmental Sciences University of Exeter Exeter UK
- UK Centre for Ecology & Hydrology Wallingford UK
| | - R. Nilus
- Forest Research Centre, Sabah Forestry Department, P.O. Box 1407, 90715 Sandakan Sabah Malaysia
| | | | - L. R. Rowland
- College of Life and Environmental Sciences University of Exeter Exeter UK
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26
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Peng G, Xiong Y, Yin M, Wang X, Zhou W, Cheng Z, Zhang YJ, Yang D. Leaf Venation Architecture in Relation to Leaf Size Across Leaf Habits and Vein Types in Subtropical Woody Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:873036. [PMID: 35599892 PMCID: PMC9121095 DOI: 10.3389/fpls.2022.873036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/21/2022] [Indexed: 05/12/2023]
Abstract
Leaves are enormously diverse in their size and venation architecture, both of which are core determinants of plant adaptation to environments. Leaf size is an important determinant of leaf function and ecological strategy, while leaf venation, the main structure for support and transport, determines the growth, development, and performance of a leaf. The scaling relationship between venation architecture and leaf size has been explored, but the relationship within a community and its potential variations among species with different vein types and leaf habits have not been investigated. Here, we measured vein traits and leaf size across 39 broad-leaved woody species within a subtropical forest community in China and analyzed the scaling relationship using ordinary least squares and standard major axis method. Then, we compared our results with the global dataset. The major vein density, and the ratio of major (1° and 2°) to minor (3° and higher) vein density both geometrically declined with leaf size across different vein types and leaf habits. Further, palmate-veined species have higher major vein density and a higher ratio of major to minor vein density at the given leaf size than pinnate-veined species, while evergreen and deciduous species showed no difference. These robust trends were confirmed by reanalyzing the global dataset using the same major vein classification as ours. We also found a tradeoff between the cell wall mass per vein length of the major vein and the major vein density. These vein scaling relationships have important implications on the optimization of leaf size, niche differentiation of coexisting species, plant drought tolerance, and species distribution.
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Affiliation(s)
- Guoquan Peng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Yingjie Xiong
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Mengqi Yin
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Xiaolin Wang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Wei Zhou
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Zhenfeng Cheng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, ME, United States
| | - Dongmei Yang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
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27
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Zhao F, Yang T, Luo C, Rao W, Yang G, Li G, Shen Z. Comparing Elevational Patterns of Taxonomic, Phylogenetic, and Functional Diversity of Woody Plants Reveal the Asymmetry of Community Assembly Mechanisms on a Mountain in the Hengduan Mountains Region. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.869258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The contributions and interaction of biotic and abiotic processes in community assembly are crucial for understanding the elevational patterns of biodiversity. The combined analyses of taxonomic, phylogenetic, and functional diversity are necessary to resolve this issue. By investigating vegetation in 24 transects sampled on Hongla Snow Mountain, in the central Hengduan Mountain Ranges in Southwest China, we delineated the elevational vegetation spectrum on the eastern and western slopes, analyzed the elevational variation in taxonomic, phylogenetic, and functional diversity of woody plant species, and compared the community structure of phylogeny and function in the low-elevational shrublands, mid-elevational forests, and alpine shrubs and meadows. The species richness, phylogenetic diversity, and functional diversity of woody plants showed nonstandard hump-shaped patterns with two peaks along the elevational gradient. The community structure of phylogeny and function (including tree height, leaf area, specific leaf area, leaf thickness, bark thickness, and wood density) clustered in the low-elevation shrub communities, being random and over-dispersed in mid-elevational forests. The phylogenic structure was over-dispersed in alpine communities, whereas the functional structure was clustered. Elevational patterns in taxonomic, phylogenetic, and functional diversity, together with the mean and variation in woody plant functional traits, suggested drought stress and freeze stress as environmental filters dominating the assembly of low and high elevation non-forest communities, and a conspicuous effect of biotic facilitation was also suggested for alpine habitats. By contrast, interspecific competition dominated the community assembly of forests at mid-elevations. The difference in biodiversity indices between the west and east slopes reflected the effects of the Indian Monsoon on the geomorphic patterns of ecosystem structure. These results increased our understanding of biodiversity patterns and underlying mechanisms in the Hengduan Mountains of Southwest China and highlighted the priorities for biodiversity conservation in this region.
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28
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Kitudom N, Fauset S, Zhou Y, Fan Z, Li M, He M, Zhang S, Xu K, Lin H. Thermal safety margins of plant leaves across biomes under a heatwave. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150416. [PMID: 34852425 DOI: 10.1016/j.scitotenv.2021.150416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Climate change has great impacts on forest ecosystems, especially with the increasing frequency of heatwaves. Thermal safety margin (TSM) calculated by the difference between body temperature and thermotolerance threshold is useful to predict thermal safety of organisms. It has been widely used for animals, whereas has rarely been reported for plants. Besides, most of the previous studies used only thermotolerance to estimate thermal safety or used thermotolerance and air temperature (Ta) to calculate TSM. However, leaf temperature (Tl) is the real "body" temperature of plant leaves. Tl decoupling from Ta might induce large error in TSM. Here, we investigated TSM of photosystem II (thermotolerance of PSII - the maximum Tl) of dominant canopy plants in four forests from tropical to temperate biomes during a heatwave, and compared the TSMs calculated by Tl (TSM.Tl) and Ta (TSM.Ta) respectively. Also, thermal related leaf traits were investigated. The results showed that both TSM. Tl and TSM.Ta decreased from the cool forests to the hot forests. TSM.Tl was highly correlated with the maximum leaf temperature (Tlmax), while had an opposite trend with thermotolerance across biomes. Thus, Tlmax instead of thermotolerance can be used to evaluate TSM. The maximum Ta (Tamax), Tlmax and leaf traits explained 68% of the variance of thermotolerance in a random forest model, where Tamax and Tlmax explained 62%. TSM.Ta could not distinguish thermal safety differences between co-occurring species. The overestimation of TSM by TSM.Ta increased from the tropical to the temperate forest, and increased with Tl within biome. Therefore, it is not recommended to use TSM.Ta in cold forests. The present study enriches the dataset of photosynthetic TSMs across biomes, proposes using Tlmax to estimate TSMs of leaves, and highlights the risk of hot dry forest during heatwaves.
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Affiliation(s)
- Nawatbhrist Kitudom
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sophie Fauset
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK
| | - Yingying Zhou
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zexin Fan
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Xishuangbanna 666303, China; Ailaoshan Station of Subtropical Forest Ecosystem Studies, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Jingdong, Yunnan 676209, China
| | - Murong Li
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; College of Biology and Chemistry, Puer University, Puer, Yunnan 665000, China
| | - Mingjian He
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; College of Biology and Chemistry, Puer University, Puer, Yunnan 665000, China
| | - Shubin Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Kun Xu
- Yunnan Lijiang Forest Ecosystem National Observation and Research Station, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Hua Lin
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Xishuangbanna 666303, China.
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29
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Warming Responses of Leaf Morphology Are Highly Variable among Tropical Tree Species. FORESTS 2022. [DOI: 10.3390/f13020219] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Leaf morphological traits vary along climate gradients, but it is currently unclear to what extent this results from acclimation rather than adaptation. Knowing so is important for predicting the functioning of long-lived organisms, such as trees, in a rapidly changing climate. We investigated the leaf morphological warming responses of 18 tropical tree species with early (ES) abd late (LS) successional strategies, planted at three sites along an elevation gradient from 2400 m a.s.l. (15.2 °C mean temperature) to 1300 m a.s.l. (20.6 °C mean temperature) in Rwanda. Leaf size expressed as leaf area (LA) and leaf mass per area (LMA) decreased, while leaf width-to-length ratio (W/L) increased with warming, but only for one third to half of the species. While LA decreased in ES species, but mostly not in LS species, changes in LMA and leaf W/L were common in both successional groups. ES species had lower LMA and higher LA and leaf W/L compared to LS species. Values of LMA and LA of juvenile trees in this study were mostly similar to corresponding data on four mature tree species in another elevation-gradient study in Rwanda, indicating that our results are applicable also to mature forest trees. We conclude that leaf morphological responses to warming differ greatly between both successional groups and individual species, with potential consequences for species competitiveness and community composition in a warmer climate.
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Tarvainen L, Wittemann M, Mujawamariya M, Manishimwe A, Zibera E, Ntirugulirwa B, Ract C, Manzi OJL, Andersson MX, Spetea C, Nsabimana D, Wallin G, Uddling J. Handling the heat - photosynthetic thermal stress in tropical trees. THE NEW PHYTOLOGIST 2022; 233:236-250. [PMID: 34655491 DOI: 10.1111/nph.17809] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/09/2021] [Indexed: 06/13/2023]
Abstract
Warming climate increases the risk for harmful leaf temperatures in terrestrial plants, causing heat stress and loss of productivity. The heat sensitivity may be particularly high in equatorial tropical tree species adapted to a thermally stable climate. Thermal thresholds of the photosynthetic system of sun-exposed leaves were investigated in three tropical montane tree species native to Rwanda with different growth and water use strategies (Harungana montana, Syzygium guineense and Entandrophragma exselsum). Measurements of chlorophyll fluorescence, leaf gas exchange, morphology, chemistry and temperature were made at three common gardens along an elevation/temperature gradient. Heat tolerance acclimated to maximum leaf temperature (Tleaf ) across the species. At the warmest sites, the thermal threshold for normal function of photosystem II was exceeded in the species with the highest Tleaf despite their higher heat tolerance. This was not the case in the species with the highest transpiration rates and lowest Tleaf . The results point to two differently effective strategies for managing thermal stress: tolerance through physiological adjustment of leaf osmolality and thylakoid membrane lipid composition, or avoidance through morphological adaptation and transpiratory cooling. More severe photosynthetic heat stress in low-transpiring montane climax species may result in a competitive disadvantage compared to high-transpiring pioneer species with more efficient leaf cooling.
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Affiliation(s)
- Lasse Tarvainen
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Maria Wittemann
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Myriam Mujawamariya
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Aloysie Manishimwe
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Etienne Zibera
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Bonaventure Ntirugulirwa
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
- Rwanda Agriculture and Animal Development Board, PO Box 5016, Kigali, Rwanda
| | - Claire Ract
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Olivier J L Manzi
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Mats X Andersson
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Donat Nsabimana
- School of Forestry and Biodiversity and Biological Sciences, University of Rwanda, Busogo, Rwanda
| | - Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
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31
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Du B, Zhu Y, Kang H, Liu C. Spatial variations in stomatal traits and their coordination with leaf traits in Quercus variabilis across Eastern Asia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 789:147757. [PMID: 34058578 DOI: 10.1016/j.scitotenv.2021.147757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 05/26/2023]
Abstract
The stomatal traits influence ecosystem carbon-water fluxes and play essential roles that enable plants to adapt to changing environmental conditions. However, how stomatal traits vary along a large climate gradient and whether stomatal traits coordinated with other leaf functional traits in response to environmental changes remain unclear. We investigated the stomatal density (SD), stomatal size (SS), and leaf traits (leaf area (LA), leaf mass per area (LMA), and vein density (VD)) of 44 in situ Quercus variabilis populations across Eastern Asia (24 to 51.8°N, 99 to 137°E) and 15 populations grown in a common garden, and evaluated their relationships with environmental factors. Stepwise multiple regression showed that the SD was significantly associated with mean annual precipitation (MAP), LMA, and VD, and the SS with latitude, mean annual temperature (MAT), mean monthly solar radiation (MMSR), and VD. The SD was positively correlated with the LMA, while the SS was negatively correlated with the VD. The SD and LMA increased with decreasing precipitation, which indicated that they may coordinate to commonly enhance plant resistance against drought. The SS decreased; however, the VD increased with temperature. This implied that plants might further reduce their SS by increasing VD limitations under global warming. In the common garden, plants exhibited a higher SD and VD and lower SS and LA compared to those in the field; however, no relation between the stomatal and leaf traits was observed. Our results suggested that stomatal traits have high environmental plasticity and are highly coordinated with other leaf functional traits in response to environmental changes. Nevertheless, this coordination may have been formed through long-term adaptations, rather than over short time spans.
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Affiliation(s)
- Baoming Du
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yanhua Zhu
- Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hongzhang Kang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; School of Design, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Chunjiang Liu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Urban Forest Ecosystem Research Station, State Forestry Administration, Shanghai 200240, China; Shanghai Yangtze River Delta Eco-environmental Change and Management Observation and Research Station, Ministry of Science and Technology, Shanghai 200240, China.
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32
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Carter KR, Wood TE, Reed SC, Butts KM, Cavaleri MA. Experimental warming across a tropical forest canopy height gradient reveals minimal photosynthetic and respiratory acclimation. PLANT, CELL & ENVIRONMENT 2021; 44:2879-2897. [PMID: 34169547 DOI: 10.1111/pce.14134] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
Tropical forest canopies cycle vast amounts of carbon, yet we still have a limited understanding of how these critical ecosystems will respond to climate warming. We implemented in situ leaf-level + 3°C experimental warming from the understory to the upper canopy of two Puerto Rican tropical tree species, Guarea guidonia and Ocotea sintenisii. After approximately 1 month of continuous warming, we assessed adjustments in photosynthesis, chlorophyll fluorescence, stomatal conductance, leaf traits and foliar respiration. Warming did not alter net photosynthetic temperature response for either species; however, the optimum temperature of Ocotea understory leaf photosynthetic electron transport shifted upward. There was no Ocotea respiratory treatment effect, while Guarea respiratory temperature sensitivity (Q10 ) was down-regulated in heated leaves. The optimum temperatures for photosynthesis (Topt ) decreased 3-5°C from understory to the highest canopy position, perhaps due to upper canopy stomatal conductance limitations. Guarea upper canopy Topt was similar to the mean daytime temperatures, while Ocotea canopy leaves often operated above Topt . With minimal acclimation to warmer temperatures in the upper canopy, further warming could put these forests at risk of reduced CO2 uptake, which could weaken the overall carbon sink strength of this tropical forest.
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Affiliation(s)
- Kelsey R Carter
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, USA
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Tana E Wood
- United States Department of Agriculture, Forest Service, International Institute of Tropical Forestry, Jardin Botánico Sur, Río Piedras, Puerto Rico, USA
| | - Sasha C Reed
- U.S. Geological Survey, Southwest Biological Science Center, Moab, Utah, USA
| | - Kaylie M Butts
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, USA
| | - Molly A Cavaleri
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, USA
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33
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Cook AM, Berry N, Milner KV, Leigh A. Water availability influences thermal safety margins for leaves. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13868] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Alicia M. Cook
- School of Life Sciences University of Technology Sydney Broadway NSW Australia
| | - Neil Berry
- School of Life Sciences University of Technology Sydney Broadway NSW Australia
| | - Kirsty V. Milner
- School of Life Sciences University of Technology Sydney Broadway NSW Australia
| | - Andrea Leigh
- School of Life Sciences University of Technology Sydney Broadway NSW Australia
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34
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Slot M, Cala D, Aranda J, Virgo A, Michaletz ST, Winter K. Leaf heat tolerance of 147 tropical forest species varies with elevation and leaf functional traits, but not with phylogeny. PLANT, CELL & ENVIRONMENT 2021; 44:2414-2427. [PMID: 33817813 DOI: 10.1111/pce.14060] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Exceeding thermal thresholds causes irreversible damage and ultimately loss of leaves. The lowland tropics are among the warmest forested biomes, but little is known about heat tolerance of tropical forest plants. We surveyed leaf heat tolerance of sun-exposed leaves from 147 tropical lowland and pre-montane forest species by determining the temperatures at which potential photosystem II efficiency based on chlorophyll a fluorescence started to decrease (TCrit ) and had decreased by 50% (T50 ). TCrit averaged 46.7°C (5th-95th percentile: 43.5°C-49.7°C) and T50 averaged 49.9°C (47.8°C-52.5°C). Heat tolerance partially adjusted to site temperature; TCrit and T50 decreased with elevation by 0.40°C and 0.26°C per 100 m, respectively, while mean annual temperature decreased by 0.63°C per 100 m. The phylogenetic signal in heat tolerance was weak, suggesting that heat tolerance is more strongly controlled by environment than by evolutionary legacies. TCrit increased with the estimated thermal time constant of the leaves, indicating that species with thermally buffered leaves maintain higher heat tolerance. Among lowland species, T50 increased with leaf mass per area, suggesting that in species with structurally more costly leaves the risk of leaf loss during hot spells is reduced. These results provide insight in variation in heat tolerance at local and regional scales.
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Affiliation(s)
- Martijn Slot
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Daniela Cala
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
- Paul H. O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana, USA
| | - Jorge Aranda
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Aurelio Virgo
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
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35
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Flo V, Martínez-Vilalta J, Mencuccini M, Granda V, Anderegg WRL, Poyatos R. Climate and functional traits jointly mediate tree water-use strategies. THE NEW PHYTOLOGIST 2021; 231:617-630. [PMID: 33893652 DOI: 10.1111/nph.17404] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
Tree water use is central to plant function and ecosystem fluxes. However, it is still unknown how organ-level water-relations traits are coordinated to determine whole-tree water-use strategies in response to drought, and whether this coordination depends on climate. Here we used a global sap flow database (SAPFLUXNET) to study the response of water use, in terms of whole-tree canopy conductance (G), to vapour pressure deficit (VPD) and to soil water content (SWC) for 142 tree species. We investigated the individual and coordinated effect of six water-relations traits (vulnerability to embolism, Huber value, hydraulic conductivity, turgor-loss point, rooting depth and leaf size) on water-use parameters, also accounting for the effect of tree height and climate (mean annual precipitation, MAP). Reference G and its sensitivity to VPD were tightly coordinated with water-relations traits rather than with MAP. Species with efficient xylem transport had higher canopy conductance but also higher sensitivity to VPD. Moreover, we found that angiosperms had higher reference G and higher sensitivity to VPD than did gymnosperms. Our results highlight the need to consider trait integration and reveal the complications and challenges of defining a single, whole-plant resource use spectrum ranging from 'acquisitive' to 'conservative'.
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Affiliation(s)
- Victor Flo
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Univ Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
| | - Jordi Martínez-Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Univ Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- ICREA, Barcelona, 08010, Spain
| | - Victor Granda
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Rafael Poyatos
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
- Univ Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, 08193, Spain
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36
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Tiwari R, Gloor E, da Cruz WJA, Schwantes Marimon B, Marimon-Junior BH, Reis SM, de Souza IA, Krause HG, Slot M, Winter K, Ashley D, Béu RG, Borges CS, Da Cunha M, Fauset S, Ferreira LDS, Gonçalves MDA, Lopes TT, Marques EQ, Mendonça NG, Mendonça NG, Noleto PT, de Oliveira CHL, Oliveira MA, Pireda S, Dos Santos Prestes NCC, Santos DM, Santos EB, da Silva ELS, de Souza IA, de Souza LJ, Vitória AP, Foyer CH, Galbraith D. Photosynthetic quantum efficiency in south-eastern Amazonian trees may be already affected by climate change. PLANT, CELL & ENVIRONMENT 2021; 44:2428-2439. [PMID: 32339294 DOI: 10.1111/pce.13770] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 03/28/2020] [Indexed: 06/11/2023]
Abstract
Tropical forests are experiencing unprecedented high-temperature conditions due to climate change that could limit their photosynthetic functions. We studied the high-temperature sensitivity of photosynthesis in a rainforest site in southern Amazonia, where some of the highest temperatures and most rapid warming in the Tropics have been recorded. The quantum yield (Fv /Fm ) of photosystem II was measured in seven dominant tree species using leaf discs exposed to varying levels of heat stress. T50 was calculated as the temperature at which Fv /Fm was half the maximum value. T5 is defined as the breakpoint temperature, at which Fv /Fm decline was initiated. Leaf thermotolerance in the rapidly warming southern Amazonia was the highest recorded for forest tree species globally. T50 and T5 varied between species, with one mid-storey species, Amaioua guianensis, exhibiting particularly high T50 and T5 values. While the T50 values of the species sampled were several degrees above the maximum air temperatures experienced in southern Amazonia, the T5 values of several species are now exceeded under present-day maximum air temperatures.
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Affiliation(s)
| | | | | | | | - Ben Hur Marimon-Junior
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Simone M Reis
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Igor Araújo de Souza
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Heinrich G Krause
- Smithsonian Tropical Research Institute, Panama City, Panama
- Institute of Plant Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Martijn Slot
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - David Ashley
- School of Geography, University of Leeds, Leeds, UK
| | - Raiane G Béu
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Camila S Borges
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Maura Da Cunha
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos Dos Goytacazes, Brazil
| | - Sophie Fauset
- Faculty of Science and Engineering, School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK
| | - Laura D S Ferreira
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | | | - Thaynara T Lopes
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Eduardo Q Marques
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Natalia G Mendonça
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Natana G Mendonça
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Pedro T Noleto
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | | | - Milene A Oliveira
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Saulo Pireda
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos Dos Goytacazes, Brazil
| | | | - Denilson M Santos
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Eduarda B Santos
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | | | - Izabel A de Souza
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Luciana J de Souza
- Universidade do Estado de Mato Grosso, Laboratório de Ecologia Vegetal, Nova Xavantina, Brazil
| | - Angela P Vitória
- Laboratório de Ciências Ambientais, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos Dos Goytacazes, Brazil
| | - Christine H Foyer
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
- School of Biosciences, University of Birmingham, Birmingham, UK
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Still CJ, Rastogi B, Page GFM, Griffith DM, Sibley A, Schulze M, Hawkins L, Pau S, Detto M, Helliker BR. Imaging canopy temperature: shedding (thermal) light on ecosystem processes. THE NEW PHYTOLOGIST 2021; 230:1746-1753. [PMID: 33666251 DOI: 10.1111/nph.17321] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Canopy temperature Tcan is a key driver of plant function that emerges as a result of interacting biotic and abiotic processes and properties. However, understanding controls on Tcan and forecasting canopy responses to weather extremes and climate change are difficult due to sparse measurements of Tcan at appropriate spatial and temporal scales. Burgeoning observations of Tcan from thermal cameras enable evaluation of energy budget theory and better understanding of how environmental controls, leaf traits and canopy structure influence temperature patterns. The canopy scale is relevant for connecting to remote sensing and testing biosphere model predictions. We anticipate that future breakthroughs in understanding of ecosystem responses to climate change will result from multiscale observations of Tcan across a range of ecosystems.
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Affiliation(s)
- Christopher J Still
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Bharat Rastogi
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, 80309, USA
- Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, 80305, USA
| | - Gerald F M Page
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Dan M Griffith
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Adam Sibley
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Mark Schulze
- H.J. Andrews Experimental Forest, Oregon State University, Blue River, OR, 97413, USA
| | - Linnia Hawkins
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Stephanie Pau
- Department of Geography, Florida State University, Tallahassee, FL, 32304, USA
| | - Matteo Detto
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08540, USA
- Smithsonian Tropical Research Institute, Balboa, Panama
| | - Brent R Helliker
- Department of Biology, University of Pennsylvania, 433 S. University Avenue, Philadelphia, PA, 19104, USA
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Boanares D, Lemos-Filho JP, Isaias RMS, França MGC. Photosynthetic heat tolerance in plants with different foliar water -uptake strategies. AMERICAN JOURNAL OF BOTANY 2021; 108:811-819. [PMID: 33891308 DOI: 10.1002/ajb2.1648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
PREMISE The distribution and even the survival of plant species are influenced by temperature. In an old climatically buffered infertile landscape (OCBIL) in Brazil, we previously characterized different strategies for foliar water uptake (FWU). It is possible that photosystem II tolerance to heat and excessive light intensity varies among species with different FWU capacities. METHODS The relationship between FWU, photoinhibition, and thermotolerance was investigated in seven species from this ecosystem. RESULTS The species with slow water absorption and high water absorption are those that presented less photoinhibition. Contrastingly, the species that have fast and low water absorption presented greater thermotolerance when their leaves are totally hydrated. However, when there is greater leaf dehydration, the most thermotolerant species were those with slow but high water absorption. CONCLUSIONS Foliar water uptake is an important trait for plants to tolerate excessive light intensity and higher temperatures. Plants in this OCBIL may be differentially affected by future global warming, and the best strategy to deal with this expected climate change is with slow and high absorption of water.
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Affiliation(s)
- Daniela Boanares
- Departamento de Botânica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, CEP 31270-901, Brasil
| | - José P Lemos-Filho
- Departamento de Botânica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, CEP 31270-901, Brasil
| | - Rosy M S Isaias
- Departamento de Botânica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, CEP 31270-901, Brasil
| | - Marcel G C França
- Departamento de Botânica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, CEP 31270-901, Brasil
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39
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Tserej O, Feeley KJ. Variation in leaf temperatures of tropical and subtropical trees are related to leaf thermoregulatory traits and not geographic distributions. Biotropica 2021. [DOI: 10.1111/btp.12919] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Olga Tserej
- Biology Department University of Miami Coral Gables FL USA
- Fairchild Tropical Botanic Garden Coral Gables FL USA
| | - Kenneth J. Feeley
- Biology Department University of Miami Coral Gables FL USA
- Fairchild Tropical Botanic Garden Coral Gables FL USA
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40
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Cavaleri MA. Cold-blooded forests in a warming world. THE NEW PHYTOLOGIST 2020; 228:1455-1457. [PMID: 33011978 DOI: 10.1111/nph.16916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/01/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Molly A Cavaleri
- College of Forest Resources & Environmental Science, Michigan Technological University, Houghton, MI, 49931, USA
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41
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Drake JE, Harwood R, Vårhammar A, Barbour MM, Reich PB, Barton CVM, Tjoelker MG. No evidence of homeostatic regulation of leaf temperature in Eucalyptus parramattensis trees: integration of CO 2 flux and oxygen isotope methodologies. THE NEW PHYTOLOGIST 2020; 228:1511-1523. [PMID: 32531796 DOI: 10.1111/nph.16733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
Thermoregulation of leaf temperature (Tleaf ) may foster metabolic homeostasis in plants, but the degree to which Tleaf is moderated, and under what environmental contexts, is a topic of debate. Isotopic studies inferred the temperature of photosynthetic carbon assimilation to be a constant value of c. 20°C; by contrast, leaf biophysical theory suggests a strong dependence of Tleaf on environmental drivers. Can this apparent disparity be reconciled? We continuously measured Tleaf and whole-crown net CO2 uptake for Eucalyptus parramattensis trees growing in field conditions in whole-tree chambers under ambient and +3°C warming conditions, and calculated assimilation-weighted leaf temperature (TL-AW ) across 265 d, varying in air temperature (Tair ) from -1 to 45°C. We compared these data to TL-AW derived from wood cellulose δ18 O. Tleaf exhibited substantial variation driven by Tair , light intensity, and vapor pressure deficit, and Tleaf was strongly linearly correlated with Tair with a slope of c. 1.0. TL-AW values calculated from cellulose δ18 O vs crown fluxes were remarkably consistent; both varied seasonally and in response to the warming treatment, tracking variation in Tair . The leaves studied here were nearly poikilothermic, with no evidence of thermoregulation of Tleaf towards a homeostatic value. Importantly, this work supports the use of cellulose δ18 O to infer TL-AW , but does not support the concept of strong homeothermic regulation of Tleaf.
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Affiliation(s)
- John E Drake
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Sustainable Resources Management, SUNY-ESF, 1 Forestry Drive, Syracuse, NY, 13210, USA
| | - Richard Harwood
- School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | - Angelica Vårhammar
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Margaret M Barbour
- School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | - Peter B Reich
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Department of Forest Resources, University of Minnesota, 1530 Cleveland Ave N., St Paul, MN, 55108, USA
| | - Craig V M Barton
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Mark G Tjoelker
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
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42
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Affiliation(s)
- Timothy M. Perez
- Department of Biology University of Miami Coral Gables FL USA
- Fairchild Tropical Botanic Garden Coral Gables FL USA
| | - Kenneth J. Feeley
- Department of Biology University of Miami Coral Gables FL USA
- Fairchild Tropical Botanic Garden Coral Gables FL USA
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43
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Kang HX, Zhu XG, Yamori W, Tang YH. Concurrent Increases in Leaf Temperature With Light Accelerate Photosynthetic Induction in Tropical Tree Seedlings. FRONTIERS IN PLANT SCIENCE 2020; 11:1216. [PMID: 32849753 PMCID: PMC7427472 DOI: 10.3389/fpls.2020.01216] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 07/27/2020] [Indexed: 05/30/2023]
Abstract
Leaf temperature changes with incident light intensity, but it is unclear how the concurrent changes influence leaf photosynthesis. We examined the time courses of CO2 gas exchanges and chlorophyll fluorescence of seedling leaves in four tropical tree species in response to lightflecks under three different temperature conditions. The three conditions were two constant temperatures at 30°C (T 30) and 40°C (T 40), and a simulated gradually changing temperature from 30 to 40°C (T dyn). The time required to reach 50% of the full photosynthetic induction under T 40 was similar to, or even larger than, that under T 30. However, the induction of assimilation rate (A) and electron transport rate of photosystem II (ETR II) and Rubisco activation process were generally accelerated under T dyn compared to those at either T 30 or T 40. The acceleration in photosynthetic induction under T dyn was significantly greater in the shade-tolerant species than in the shade-intolerant species. A modified photosynthetic limitation analysis indicated that the acceleration was likely to be mainly due to ETR II at the early stage of photosynthetic induction. The study suggests that concurrent increases in leaf temperature with light may increase leaf carbon gain under highly fluctuating light in tropical tree seedlings, particularly in shade-tolerant species.
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Affiliation(s)
- Hui-Xing Kang
- Institute of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of Ministry of Education, Peking University, Beijing, China
| | - Xin-Guang Zhu
- Center of Excellence for Molecular Plant Sciences and State Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences, Shanghai, China
| | - Wataru Yamori
- Institute for Sustainable Agro-Ecosystem Services, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yan-Hong Tang
- Institute of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of Ministry of Education, Peking University, Beijing, China
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44
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Li Y, Reich PB, Schmid B, Shrestha N, Feng X, Lyu T, Maitner BS, Xu X, Li Y, Zou D, Tan Z, Su X, Tang Z, Guo Q, Feng X, Enquist BJ, Wang Z. Leaf size of woody dicots predicts ecosystem primary productivity. Ecol Lett 2020; 23:1003-1013. [PMID: 32249502 PMCID: PMC7384143 DOI: 10.1111/ele.13503] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 01/20/2020] [Accepted: 02/03/2020] [Indexed: 02/07/2023]
Abstract
A key challenge in ecology is to understand the relationships between organismal traits and ecosystem processes. Here, with a novel dataset of leaf length and width for 10 480 woody dicots in China and 2374 in North America, we show that the variation in community mean leaf size is highly correlated with the variation in climate and ecosystem primary productivity, independent of plant life form. These relationships likely reflect how natural selection modifies leaf size across varying climates in conjunction with how climate influences canopy total leaf area. We find that the leaf size-primary productivity functions based on the Chinese dataset can predict productivity in North America and vice-versa. In addition to advancing understanding of the relationship between a climate-driven trait and ecosystem functioning, our findings suggest that leaf size can also be a promising tool in palaeoecology for scaling from fossil leaves to palaeo-primary productivity of woody ecosystems.
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Affiliation(s)
- Yaoqi Li
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
| | - Peter B. Reich
- Department of Forest ResourcesUniversity of MinnesotaSt. PaulMN55108USA
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNSW2751Australia
| | - Bernhard Schmid
- Department of GeographyRemote Sensing LaboratoriesUniversity of ZurichWinterthurerstrasse 1908057ZurichSwitzerland
| | - Nawal Shrestha
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
- Institute of Innovation EcologyLanzhou UniversityLanzhou730000China
| | - Xiao Feng
- Institute of the EnvironmentUniversity of ArizonaTucsonArizona85721USA
| | - Tong Lyu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
| | - Brian S. Maitner
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonAZ85721USA
| | - Xiaoting Xu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
- Key Laboratory of Bio‐Resource and Eco‐Environment of Ministry of EducationCollege of Life SciencesSichuan UniversityChengdu610065SichuanChina
| | - Yichao Li
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
| | - Dongting Zou
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
| | - Zheng‐Hong Tan
- College of Environment and EcologyHainan UniversityHaikouHainan570228China
| | - Xiangyan Su
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
| | - Zhiyao Tang
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
| | - Qinghua Guo
- State Key Laboratory of Vegetation and Environmental ChangeInstitute of BotanyChinese Academy of SciencesBeijing100093China
| | - Xiaojuan Feng
- State Key Laboratory of Vegetation and Environmental ChangeInstitute of BotanyChinese Academy of SciencesBeijing100093China
| | - Brian J. Enquist
- Institute of the EnvironmentUniversity of ArizonaTucsonArizona85721USA
- The Santa Fe InstituteSanta FeNM87501USA
| | - Zhiheng Wang
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of EducationCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China
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Hernández GG, Winter K, Slot M. Similar temperature dependence of photosynthetic parameters in sun and shade leaves of three tropical tree species. TREE PHYSIOLOGY 2020; 40:637-651. [PMID: 32083285 DOI: 10.1093/treephys/tpaa015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 02/12/2020] [Accepted: 02/12/2020] [Indexed: 06/10/2023]
Abstract
Photosynthetic carbon uptake by tropical forests is of critical importance in regulating the earth's climate, but rising temperatures threaten this stabilizing influence of tropical forests. Most research on how temperature affects photosynthesis focuses on fully sun-exposed leaves, and little is known about shade leaves, even though shade leaves greatly outnumber sun leaves in lowland tropical forests. We measured temperature responses of light-saturated photosynthesis, stomatal conductance, and the biochemical parameters VCMax (maximum rate of RuBP carboxylation) and JMax (maximum rate of RuBP regeneration, or electron transport) on sun and shade leaves of mature tropical trees of three species in Panama. As expected, biochemical capacities and stomatal conductance were much lower in shade than in sun leaves, leading to lower net photosynthesis rates. However, the key temperature response traits of these parameters-the optimum temperature (TOpt) and the activation energy-did not differ systematically between sun and shade leaves. Consistency in the JMax to VCMax ratio further suggested that shade leaves are not acclimated to lower temperatures. For both sun and shade leaves, stomatal conductance had the lowest temperature optimum (~25 °C), followed by net photosynthesis (~30 °C), JMax (~34 °C) and VCMax (~38 °C). Stomatal conductance of sun leaves decreased more strongly with increasing vapor pressure deficit than that of shade leaves. Consistent with this, modeled stomatal limitation of photosynthesis increased with increasing temperature in sun but not shade leaves. Collectively, these results suggest that modeling photosynthetic carbon uptake in multi-layered canopies does not require independent parameterization of the temperature responses of the biochemical controls over photosynthesis of sun and shade leaves. Nonetheless, to improve the representation of the shade fraction of carbon uptake dynamics in tropical forests, better understanding of stomatal sensitivity of shade leaves to temperature and vapor pressure deficit will be required.
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Affiliation(s)
- Georgia G Hernández
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama, Republic of Panama
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama, Republic of Panama
| | - Martijn Slot
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama, Republic of Panama
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46
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Diverging Responses of Two Subtropical Tree Species (Schima superba and Cunninghamia lanceolata) to Heat Waves. FORESTS 2020. [DOI: 10.3390/f11050513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The frequency and intensity of heat waves (HWs) has increased in subtropical regions in recent years. The mechanism underlying the HW response of subtropical trees remains unclear. In this study, we conducted an experiment with broad-leaved Schima superba (S. superba) and coniferous Cunninghamia lanceolata (C. lanceolata) seedlings to examine HW (5-day long) effects on stem water transport, leaf water use efficiency (WUE), morphology and growth, and to elucidate differences in the responses of both species. Our results indicated that HWs can significantly reduce hydraulic conductivity in both species. C. lanceolata experienced significant xylem embolism, with the percentage loss of conductivity (PLC) increasing by 40%, while S. superba showed a non-significant increase in PLC (+25%). Furthermore, HW also caused a reduction in photosynthesis rates (An), but transpiration rates (Tr) increased on the 5th day of the HW, together leading to a significant decrease in leaf WUE. From diurnal dynamics, we observed that the HW caused significant decrease of S. superba An only in the morning, but nearly the all day for C. lanceolata. During the morning, with a high vapor pressure deficit (VPD) environment, the HW increased Tr, which contributed a lot to latently cooling the foliage. In comparing the two tree species, we found that HW effects on S. superba were mostly short-term, with leaf senescence but limited or no xylem embolism. The surviving S. superba recovered rapidly, forming new branches and leaves, aided by their extensive root systems. For C. lanceolata, continued seedling growth initially but with subsequent xylem embolism and withering of shoots, led to stunted recovery and regrowth. In conclusion, apart from the direct thermal impacts caused by HW, drought stress was the main cause of significant negative effects on plant water transport and the photosynthetic system. Furthermore, S. superba and C. lanceolata showed clearly different responses to HW, which implies that the response mechanisms of broad-leaved and coniferous tree species to climate change can differ.
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47
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Taylor TC, Smith MN, Slot M, Feeley KJ. The capacity to emit isoprene differentiates the photosynthetic temperature responses of tropical plant species. PLANT, CELL & ENVIRONMENT 2019; 42:2448-2457. [PMID: 30993708 DOI: 10.1111/pce.13564] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/08/2019] [Accepted: 04/12/2019] [Indexed: 05/07/2023]
Abstract
Experimental research shows that isoprene emission by plants can improve photosynthetic performance at high temperatures. But whether species that emit isoprene have higher thermal limits than non-emitting species remains largely untested. Tropical plants are adapted to narrow temperature ranges and global warming could result in significant ecosystem restructuring due to small variations in species' thermal tolerances. We compared photosynthetic temperature responses of 26 co-occurring tropical tree and liana species to test whether isoprene-emitting species are more tolerant to high temperatures. We classified species as isoprene emitters versus non-emitters based on published datasets. Maximum temperatures for net photosynthesis were ~1.8°C higher for isoprene-emitting species than for non-emitters, and thermal response curves were 24% wider; differences in optimum temperatures (Topt ) or photosynthetic rates at Topt were not significant. Modelling the carbon cost of isoprene emission, we show that even strong emission rates cause little reduction in the net carbon assimilation advantage over non-emitters at supraoptimal temperatures. Isoprene emissions may alleviate biochemical limitations, which together with stomatal conductance, co-limit photosynthesis above Topt . Our findings provide evidence that isoprene emission may be an adaptation to warmer thermal niches, and that emitting species may fare better under global warming than co-occurring non-emitting species.
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Affiliation(s)
- Tyeen C Taylor
- Department of Biological Sciences, University of Miami, Coral Gables, FL
| | - Marielle N Smith
- Department of Forestry, Michigan State University, East Lansing, MI
| | - Martijn Slot
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
| | - Kenneth J Feeley
- Department of Biological Sciences, University of Miami, Coral Gables, FL
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48
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Slot M, Krause GH, Krause B, Hernández GG, Winter K. Photosynthetic heat tolerance of shade and sun leaves of three tropical tree species. PHOTOSYNTHESIS RESEARCH 2019; 141:119-130. [PMID: 30054784 DOI: 10.1007/s11120-018-0563-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/21/2018] [Indexed: 06/08/2023]
Abstract
Previous studies of heat tolerance of tropical trees have focused on canopy leaves exposed to full sunlight and high temperatures. However, in lowland tropical forests with leaf area indices of 5-6, the vast majority of leaves experience varying degrees of shade and a reduced heat load compared to sun leaves. Here we tested whether heat tolerance is lower in shade than in sun leaves. For three tropical tree species, Calophyllum inophyllum, Inga spectabilis, and Ormosia macrocalyx, disks of fully developed shade and sun leaves were subjected to 15-min heat treatments, followed by measurement of chlorophyll a fluorescence after 48 h of recovery. In two of the three species, the temperature causing a 50% decrease of the fluorescence ratio Fv/Fm (T50) was significantly lower (by ~ 1.0 °C) in shade than in sun leaves, indicating a moderately decreased heat tolerance of shade leaves. In shade leaves of these two species, the rise in initial fluorescence, F0, also occurred at lower temperatures. In the third species, there was no shade-sun difference in T50. In situ measurements of photosynthetic CO2 assimilation showed that the optimum temperature for photosynthesis tended to be lower in shade leaves, although differences were not significant. At supra-optimal temperatures, photosynthesis was largely constrained by stomatal conductance, and the high-temperature CO2 compensation point, TMax, occurred at considerably lower temperatures than T50. Our study demonstrates that the temperature response of shade leaves of tropical trees differs only marginally from that of sun leaves, both in terms of heat tolerance and photosynthetic performance.
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Affiliation(s)
- Martijn Slot
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama City, Panama.
| | - G Heinrich Krause
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama City, Panama
- Institute of Plant Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Barbara Krause
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama City, Panama
| | - Georgia G Hernández
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama City, Panama
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama City, Panama
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49
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Aspinwall MJ, Pfautsch S, Tjoelker MG, Vårhammar A, Possell M, Drake JE, Reich PB, Tissue DT, Atkin OK, Rymer PD, Dennison S, Van Sluyter SC. Range size and growth temperature influence Eucalyptus species responses to an experimental heatwave. GLOBAL CHANGE BIOLOGY 2019; 25:1665-1684. [PMID: 30746837 DOI: 10.1111/gcb.14590] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/03/2019] [Accepted: 02/04/2019] [Indexed: 05/24/2023]
Abstract
Understanding forest tree responses to climate warming and heatwaves is important for predicting changes in tree species diversity, forest C uptake, and vegetation-climate interactions. Yet, tree species differences in heatwave tolerance and their plasticity to growth temperature remain poorly understood. In this study, populations of four Eucalyptus species, two with large range sizes and two with comparatively small range sizes, were grown under two temperature treatments (cool and warm) before being exposed to an equivalent experimental heatwave. We tested whether the species with large and small range sizes differed in heatwave tolerance, and whether trees grown under warmer temperatures were more tolerant of heatwave conditions than trees grown under cooler temperatures. Visible heatwave damage was more common and severe in the species with small rather than large range sizes. In general, species that showed less tissue damage maintained higher stomatal conductance, lower leaf temperatures, larger increases in isoprene emissions, and less photosynthetic inhibition than species that showed more damage. Species exhibiting more severe visible damage had larger increases in heat shock proteins (HSPs) and respiratory thermotolerance (Tmax ). Thus, across species, increases in HSPs and Tmax were positively correlated, but inversely related to increases in isoprene emissions. Integration of leaf gas-exchange, isoprene emissions, proteomics, and respiratory thermotolerance measurements provided new insight into mechanisms underlying variability in tree species heatwave tolerance. Importantly, warm-grown seedlings were, surprisingly, more susceptible to heatwave damage than cool-grown seedlings, which could be associated with reduced enzyme concentrations in leaves. We conclude that species with restricted range sizes, along with trees growing under climate warming, may be more vulnerable to heatwaves of the future.
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Affiliation(s)
- Michael J Aspinwall
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
- Department of Biology, University of North Florida, Jacksonville, Florida
| | - Sebastian Pfautsch
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Mark G Tjoelker
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Angelica Vårhammar
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Malcolm Possell
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - John E Drake
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
- Forest and Natural Resources Management, SUNY-ESF, Syracuse, New York
| | - Peter B Reich
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
- Department of Forest Resources, University of Minnesota, Minnesota
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Owen K Atkin
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Paul D Rymer
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Siobhan Dennison
- Department of Biological Science, Macquarie University, North Ryde, NSW, Australia
| | - Steven C Van Sluyter
- Department of Biological Science, Macquarie University, North Ryde, NSW, Australia
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