1
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Li S, Li S, Agathokleous E, Hao G, Wang S, Feng Z. Leaf water relations determine the trade-off between ozone resistance and stomatal functionality in urban tree species. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38693830 DOI: 10.1111/pce.14934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/25/2024] [Accepted: 04/19/2024] [Indexed: 05/03/2024]
Abstract
Urban trees possess different capacities to mitigate ozone (O3) pollution through stomatal uptake. Stomatal closure protects trees from oxidative damage but limits their growth. To date, it is unclear how plant hydraulic function affect stomatal behaviour and determine O3 resistance. We assessed gas exchange and hydraulic traits in three subtropical urban tree species, Celtis sinensis, Quercus acutissima, and Q. nuttallii, under nonfiltered ambient air (NF) and elevated O3 (NF60). NF60 decreased photosynthetic rate (An) and stomatal conductance (gs) only in Q. acutissima and Q. nuttallii. Maintained An in C. sinensis suggested high O3 resistance and was attributed to higher leaf capacitance at the full turgor. However, this species exhibited a reduced stomatal sensitivity to vapour pressure deficit and an increased minimal gs under NF60. Such stomatal dysfunction did not decrease intrinsic water use efficiency (WUE) due to a tight coupling of An and gs. Conversely, Q. acutissima and Q. nuttallii showed maintained stomatal sensitivity and increased WUE, primarily correlated with gs and leaf water relations, including relative water content and osmotic potential at turgor loss point. Our findings highlight a trade-off between O3 resistance and stomatal functionality, with efficient stomatal control reducing the risk of hydraulic failure under combined stresses.
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Affiliation(s)
- Shenglan Li
- School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, China
- Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration (ECSS-CMA), School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing, China
| | - Shuangjiang Li
- Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration (ECSS-CMA), School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing, China
- College of Resource and Environment, Anhui Science and Technology University, Fengyang, China
| | - Evgenios Agathokleous
- Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration (ECSS-CMA), School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing, China
| | - Guangyou Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Shenglei Wang
- Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration (ECSS-CMA), School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing, China
| | - Zhaozhong Feng
- Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration (ECSS-CMA), School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing, China
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2
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Castillo-Argaez R, Sapes G, Mallen N, Lippert A, John GP, Zare A, Hammond WM. Spectral ecophysiology: hyperspectral pressure-volume curves to estimate leaf turgor loss. THE NEW PHYTOLOGIST 2024; 242:935-946. [PMID: 38482720 DOI: 10.1111/nph.19669] [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: 11/28/2023] [Accepted: 02/19/2024] [Indexed: 04/12/2024]
Abstract
Turgor loss point (TLP) is an important proxy for plant drought tolerance, species habitat suitability, and drought-induced plant mortality risk. Thus, TLP serves as a critical tool for evaluating climate change impacts on plants, making it imperative to develop high-throughput and in situ methods to measure TLP. We developed hyperspectral pressure-volume curves (PV curves) to estimate TLP using leaf spectral reflectance. We used partial least square regression models to estimate water potential (Ψ) and relative water content (RWC) for two species, Frangula caroliniana and Magnolia grandiflora. RWC and Ψ's model for each species had R2 ≥ 0.7 and %RMSE = 7-10. We constructed PV curves with model estimates and compared the accuracy of directly measured and spectra-predicted TLP. Our findings indicate that leaf spectral measurements are an alternative method for estimating TLP. F. caroliniana TLP's values were -1.62 ± 0.15 (means ± SD) and -1.62 ± 0.34 MPa for observed and reflectance predicted, respectively (P > 0.05), while M. grandiflora were -1.78 ± 0.34 and -1.66 ± 0.41 MPa (P > 0.05). The estimation of TLP through leaf reflectance-based PV curves opens a broad range of possibilities for future research aimed at understanding and monitoring plant water relations on a large scale with spectral ecophysiology.
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Affiliation(s)
| | - Gerard Sapes
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
| | - Nicole Mallen
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
| | - Alston Lippert
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
| | - Grace P John
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Alina Zare
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - William M Hammond
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
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3
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Mencuccini M, Anderegg WRL, Binks O, Knipfer T, Konings AG, Novick K, Poyatos R, Martínez-Vilalta J. A new empirical framework to quantify the hydraulic effects of soil and atmospheric drivers on plant water status. GLOBAL CHANGE BIOLOGY 2024; 30:e17222. [PMID: 38450813 DOI: 10.1111/gcb.17222] [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: 12/06/2023] [Revised: 02/12/2024] [Accepted: 02/12/2024] [Indexed: 03/08/2024]
Abstract
Metrics to quantify regulation of plant water status at the daily as opposed to the seasonal scale do not presently exist. This gap is significant since plants are hypothesised to regulate their water potential not only with respect to slowly changing soil drought but also with respect to faster changes in air vapour pressure deficit (VPD), a variable whose importance for plant physiology is expected to grow because of higher temperatures in the coming decades. We present a metric, the stringency of water potential regulation, that can be employed at the daily scale and quantifies the effects exerted on plants by the separate and combined effect of soil and atmospheric drought. We test our theory using datasets from two experiments where air temperature and VPD were experimentally manipulated. In contrast to existing metrics based on soil drought that can only be applied at the seasonal scale, our metric successfully detects the impact of atmospheric warming on the regulation of plant water status. We show that the thermodynamic effect of VPD on plant water status can be isolated and compared against that exerted by soil drought and the covariation between VPD and soil drought. Furthermore, in three of three cases, VPD accounted for more than 5 MPa of potential effect on leaf water potential. We explore the significance of our findings in the context of potential future applications of this metric from plant to ecosystem scale.
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Affiliation(s)
| | - William R L Anderegg
- Wilkes Center for Climate Science and Policy, University of Utah, Salt Lake City, Utah, USA
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | | | - Thorsten Knipfer
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Kim Novick
- University of Indiana, Bloomington, Indiana, USA
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4
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Yao K, Zhang A, Rang B, Yang J, Liu Y, Wu Y. Hydrological niche regulation induced by different resistance strategies facilitates coexistence of P. longipes and L. communis under drought stress. PHYSIOLOGIA PLANTARUM 2023; 175:e14072. [PMID: 38148219 DOI: 10.1111/ppl.14072] [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: 05/16/2023] [Accepted: 10/14/2023] [Indexed: 12/28/2023]
Abstract
Under global warming, the availability of water resources is one of the most important factors affecting trait evolution and plant species distribution across terrestrial ecosystems, and the relationships between drought resistance strategies and the hydrological niche characteristics of plants are worth studying. We continuously monitored physiological drought response parameters such as gs , Tr , proline, soluble sugar, gene expression and activities of SOD, POD, and CAT to assess drought resistance strategies of Platycarya longipes and Lindera communis; determined plant soil hydrological niche separation by stable H and O isotope analysis; and analysed the effects of interspecific water competition by comparing the differences in morphological and physiological parameters between solo and mixed planting. Under drought stress, L. communis exhibited a drought avoidance strategy, and P. longipes exhibited a drought tolerance strategy. L. communis utilized the water within the shallow soil layer, while P. longipes mainly utilized the water in the deeper soil layer; there were fewer parameters with significant differences between the solo planting and the mixed planting of L. communis compared to P. longipes. Overall, P. longipes benefited from coexistence with L. communis under drought stress, which may be because L. communis employs a drought avoidance strategy, reducing soil water consumption in the drought environment. These results suggested that differences in functional traits or resistance strategies among species benefit species' coexistence in a community under drought stress.
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Affiliation(s)
- Kai Yao
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou, China
| | - Aoli Zhang
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou, China
| | - Bo Rang
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou, China
| | - Junting Yang
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou, China
| | - Yingliang Liu
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou, China
| | - Yanyou Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou, China
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5
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Guo B, Arndt SK, Miller RE, Szota C, Farrell C. How does leaf succulence relate to plant drought resistance in woody shrubs? TREE PHYSIOLOGY 2023; 43:1501-1513. [PMID: 37208014 PMCID: PMC10652328 DOI: 10.1093/treephys/tpad066] [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: 09/01/2022] [Revised: 04/13/2023] [Accepted: 05/15/2023] [Indexed: 05/21/2023]
Abstract
Succulence describes the amount of water stored in cells or organs, regardless of plant life-form, including woody and herbaceous plants. In dry environments, plants with greater survival often have greater leaf succulence. However, it is unclear how leaf succulence relates to plant drought resistance strategies, including isohydry (closing stomata to maintain leaf water status) and anisohydry (adjusting cell turgor to tolerate low leaf water status), which exist on a continuum that can be quantified by hydroscape area (larger hydroscape area indicates more anisohydric). We evaluated 12 woody species with differing leaf succulence in a glasshouse dry-down experiment to determine relationships among leaf succulence (degree of leaf succulence, leaf succulent quotient and leaf thickness) and plant drought response (hydroscape area, plant water use, turgor loss point and predawn leaf water potential when transpiration ceased). Hydroscape areas ranged from 0.72 (Carpobrotus modestus S.T.Blake; crassulacean acid metabolism (CAM) plants) to 7.01 MPa2 (Rhagodia spinescens R.Br.; C3 plants), suggesting that C. modestus was more isohydric and R. spinescens was more anisohydric. More isohydric species C. modestus, Carpobrotus rossii (Haw.) Schwantes and Disphyma crassifolium (L.) L.Bolus (CAM plants) had greater leaf succulence, lower root allocation, used stored water and ceased transpiration at higher predawn leaf water potential, shortly after reaching their turgor loss point. The remaining nine species that are not CAM plants had larger hydroscape areas and ceased transpiration at lower predawn leaf water potential. Greater leaf succulence was not related to cumulative water loss until transpiration ceased in drying soils. All 12 species had high turgor loss points (-1.32 to -0.59 MPa), but turgor loss point was not related to hydroscape area or leaf succulence. Our data suggest that overall greater leaf succulence was related to isohydry, but this may have been influenced by the fact that these species were also CAM plants.
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Affiliation(s)
- Bihan Guo
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria 3121, Australia
| | - Stefan K Arndt
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria 3121, Australia
| | - Rebecca E Miller
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria 3121, Australia
- Royal Botanic Gardens Victoria, Birdwood Avenue, Melbourne, Victoria 3004, Australia
| | - Christopher Szota
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria 3121, Australia
| | - Claire Farrell
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria 3121, Australia
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6
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Thompson RA, Adams HD, Breshears DD, Collins AD, Dickman LT, Grossiord C, Manrique-Alba À, Peltier DM, Ryan MG, Trowbridge AM, McDowell NG. No carbon storage in growth-limited trees in a semi-arid woodland. Nat Commun 2023; 14:1959. [PMID: 37029120 PMCID: PMC10081995 DOI: 10.1038/s41467-023-37577-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 03/21/2023] [Indexed: 04/09/2023] Open
Abstract
Plant survival depends on a balance between carbon supply and demand. When carbon supply becomes limited, plants buffer demand by using stored carbohydrates (sugar and starch). During drought, NSCs (non-structural carbohydrates) may accumulate if growth stops before photosynthesis. This expectation is pervasive, yet few studies have combined simultaneous measurements of drought, photosynthesis, growth, and carbon storage to test this. Using a field experiment with mature trees in a semi-arid woodland, we show that growth and photosynthesis slow in parallel as [Formula: see text] declines, preventing carbon storage in two species of conifer (J. monosperma and P. edulis). During experimental drought, growth and photosynthesis were frequently co-limited. Our results point to an alternative perspective on how plants use carbon that views growth and photosynthesis as independent processes both regulated by water availability.
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Affiliation(s)
- R Alexander Thompson
- School of the Environment, Washington State University, Pullman, WA, 99164, USA.
| | - Henry D Adams
- School of the Environment, Washington State University, Pullman, WA, 99164, USA
| | - David D Breshears
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85719, USA
| | - Adam D Collins
- Los Alamos National Laboratory, Earth & Environmental Sciences Division, Los Alamos, NM, USA
| | - L Turin Dickman
- Los Alamos National Laboratory, Earth & Environmental Sciences Division, Los Alamos, NM, USA
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, CH-1015, Lausanne, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, CH-1015, Lausanne, Switzerland
| | | | - Drew M Peltier
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Michael G Ryan
- Department of Ecosystem Science and Sustainability, Colorado State University, Fort Collins, CO, 80523, USA
- USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO, 80526, USA
| | - Amy M Trowbridge
- Department of Entomology, University of Wisconsin, Madison, WI, 53706, USA
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164-4236, USA
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7
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McCulloh KA, Augustine SP, Goke A, Jordan R, Krieg CP, O’Keefe K, Smith DD. At least it is a dry cold: the global distribution of freeze-thaw and drought stress and the traits that may impart poly-tolerance in conifers. TREE PHYSIOLOGY 2023; 43:1-15. [PMID: 36094836 PMCID: PMC9833871 DOI: 10.1093/treephys/tpac102] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 07/20/2022] [Accepted: 08/30/2022] [Indexed: 05/25/2023]
Abstract
Conifers inhabit some of the most challenging landscapes where multiple abiotic stressors (e.g., aridity, freezing temperatures) often co-occur. Physiological tolerance to multiple stressors ('poly-tolerance') is thought to be rare because exposure to one stress generally limits responses to another through functional trade-offs. However, the capacity to exhibit poly-tolerance may be greater when combined abiotic stressors have similar physiological impacts, such as the disruption of hydraulic function imposed by drought or freezing. Here, we reviewed empirical data in light of theoretical expectations for conifer adaptations to drought and freeze-thaw cycles with particular attention to hydraulic traits of the stem and leaf. Additionally, we examined the commonality and spatial distribution of poly-stress along indices of these combined stressors. We found that locations with the highest values of our poly-stress index (PSi) are characterized by moderate drought and moderate freeze-thaw, and most of the global conifer distribution occupies areas of moderate poly-stress. Among traits examined, we found diverse responses to the stressors. Turgor loss point did not correlate with freeze-thaw or drought stress individually, but did with the PSi, albeit inverse to what was hypothesized. Leaf mass per area was more strongly linked with drought stress than the poly-stress and not at all with freeze-thaw stress. In stems, the water potential causing 50% loss of hydraulic conductivity became more negative with increasing drought stress and poly-stress but did not correlate with freeze-thaw stress. For these traits, we identified a striking lack of coverage for substantial portions of species ranges, particularly at the upper boundaries of their respective PSis, demonstrating a critical gap in our understanding of trait prevalence and plasticity along these stress gradients. Future research should investigate traits that confer tolerance to both freeze-thaw and drought stress in a wide range of species across broad geographic scales.
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Affiliation(s)
| | - Steven P Augustine
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Alex Goke
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Rachel Jordan
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Christopher P Krieg
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Kimberly O’Keefe
- Department of Biological Sciences, Saint Edward’s University, Austin, TX 78704, USA
| | - Duncan D Smith
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
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8
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Feng X, Zhong L, Tian Q, Zhao W. Leaf water potential-dependent leaflet closure contributes to legume leaves cool down and drought avoidance under diurnal drought stress. TREE PHYSIOLOGY 2022; 42:2239-2251. [PMID: 35939343 DOI: 10.1093/treephys/tpac075] [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: 03/14/2022] [Accepted: 07/02/2022] [Indexed: 06/15/2023]
Abstract
Efficient thermoregulation under diurnal drought stress protects leaves from photosystem damage and water supply-demand imbalance, yet the cool effect and drought avoidance by leaflet closure have not been well understood. We investigated the cool effect and the drought avoidance of leaflet closure in legume species that survived in the semi-arid region facing seasonal and diurnal drought stress. The results showed that leaflet closure effectively cooled down legume leaves through a reduction of projected leaflet area and the cosine of the angle of incidence (cos i). The leaflet closure was strongly dependent on leaf water potential (Ψleaf). In addition, by characterizing the sequence of key leaf drought response traits, we found leaflet closure occurred after stomatal closure and reduced transpiration rate but before hydraulic failure and turgor loss point (Ψtlp). The meta-analysis also showed that the leaflet closure and cos i decreased after the stomatal conductance declined but before midday. These results imply that Ψleaf-dependent leaflet closure as an alternative to transpiration for leaflet cooling down and as a protective drought avoidance strategy assisting sessile legume plants survival under drought stress.
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Affiliation(s)
- Xiangyan Feng
- Linze Inland River Basin Research Station, Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100029, China
| | - Lingfei Zhong
- College of Geography and Environment Science, Northwest Normal University, Lanzhou 730070, China
| | - Quanyan Tian
- Linze Inland River Basin Research Station, Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Wenzhi Zhao
- Linze Inland River Basin Research Station, Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
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9
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Chen Z, Li S, Wan X, Liu S. Strategies of tree species to adapt to drought from leaf stomatal regulation and stem embolism resistance to root properties. FRONTIERS IN PLANT SCIENCE 2022; 13:926535. [PMID: 36237513 PMCID: PMC9552884 DOI: 10.3389/fpls.2022.926535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
Considerable evidences highlight the occurrence of increasing widespread tree mortality as a result of global climate change-associated droughts. However, knowledge about the mechanisms underlying divergent strategies of various tree species to adapt to drought has remained remarkably insufficient. Leaf stomatal regulation and embolism resistance of stem xylem serves as two important strategies for tree species to prevent hydraulic failure and carbon starvation, as comprising interconnected physiological mechanisms underlying drought-induced tree mortality. Hence, the physiological and anatomical determinants of leaf stomatal regulation and stems xylem embolism resistance are evaluated and discussed. In addition, root properties related to drought tolerance are also reviewed. Species with greater investment in leaves and stems tend to maintain stomatal opening and resist stem embolism under drought conditions. The coordination between stomatal regulation and stem embolism resistance are summarized and discussed. Previous studies showed that hydraulic safety margin (HSM, the difference between minimum water potential and that causing xylem dysfunction) is a significant predictor of tree species mortality under drought conditions. Compared with HSM, stomatal safety margin (the difference between water potential at stomatal closure and that causing xylem dysfunction) more directly merge stomatal regulation strategies with xylem hydraulic strategies, illustrating a comprehensive framework to characterize plant response to drought. A combination of plant traits reflecting species' response and adaptation to drought should be established in the future, and we propose four specific urgent issues as future research priorities.
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Affiliation(s)
- Zhicheng Chen
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Shan Li
- Department of Environmental Science and Ecology, School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi’an, China
| | - Xianchong Wan
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing, China
| | - Shirong Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
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10
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Fuenzalida TI, Binks O, Bryant CJ, Wolfe J, Ball MC. Monitoring plant water status via static uniaxial compression of the leaf lamina. PLANT, CELL & ENVIRONMENT 2022; 45:2589-2606. [PMID: 35733289 DOI: 10.1111/pce.14383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/16/2022] [Accepted: 06/19/2022] [Indexed: 06/15/2023]
Abstract
Turgor pressure is an essential, but difficult to measure indicator of plant water status. Turgor has been quantified by localized compression of cells or tissues, but a simple method to perform these measurements is lacking. We hypothesized that changes in leaf turgidity can be monitored by uniaxially compressing the leaf lamina and measuring the mechanical stress under a constrained thickness (stress relaxation) and that changes in leaf water content can be monitored by measuring the leaf thickness under constant mechanical stress. Using a simple, custom-built leaf squeeze-flow rheometer, we performed different compression tests on leaves from 13 plant species. The mechanical stress measured during stress relaxation was correlated with leaf bulk turgor pressure (R2 > 0.95) and thus with balancing pressure (R2 > 0.94); the leaf thickness measured under constant mechanical stress was correlated with relative water content (R2 > 0.74). The coefficients of these relationships were related to the leaf bulk osmotic pressure at the turgor-loss point. An idealized average-cell model suggests that, under isothermal conditions, the stationary bulk modulus during compression is largely determined by the bulk osmotic pressure. Our study presents an inexpensive, accessible and automatable method to monitor plant water status noninvasively.
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Affiliation(s)
- Tomás I Fuenzalida
- Plant Science Division, Research School of Biology, The Australian National University, Acton, Australia
| | - Oliver Binks
- Plant Science Division, Research School of Biology, The Australian National University, Acton, Australia
| | - Callum J Bryant
- Plant Science Division, Research School of Biology, The Australian National University, Acton, Australia
| | - Joe Wolfe
- School of Physics, UNSW, Sydney, NSW, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, The Australian National University, Acton, Australia
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11
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Limousin JM, Roussel A, Rodríguez-Calcerrada J, Torres-Ruiz JM, Moreno M, Garcia de Jalon L, Ourcival JM, Simioni G, Cochard H, Martin-StPaul N. Drought acclimation of Quercus ilex leaves improves tolerance to moderate drought but not resistance to severe water stress. PLANT, CELL & ENVIRONMENT 2022; 45:1967-1984. [PMID: 35394675 DOI: 10.1111/pce.14326] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/12/2022] [Accepted: 03/22/2022] [Indexed: 06/14/2023]
Abstract
Increasing temperature and drought can result in leaf dehydration and defoliation even in drought-adapted tree species such as the Mediterranean evergreen Quercus ilex L. The stomatal regulation of leaf water potential plays a central role in avoiding this phenomenon and is constrained by a suite of leaf traits including hydraulic conductance and vulnerability, hydraulic capacitance, minimum conductance to water vapour, osmotic potential and cell wall elasticity. We investigated whether the plasticity in these traits may improve leaf tolerance to drought in two long-term rainfall exclusion experiments in Mediterranean forests. Osmotic adjustment was observed to lower the water potential at turgor loss in the rainfall-exclusion treatments, thus suggesting a stomatal closure at more negative water potentials and a more anisohydric behaviour in drier conditions. Conversely, leaf hydraulic conductance and vulnerability did not exhibit any plasticity between treatments so the hydraulic safety margins were narrower in the rainfall-exclusion treatments. The sequence of leaf responses to seasonal drought and dehydration was conserved among treatments and sites but trees were more likely to suffer losses of turgor and hydraulic functioning in the rainfall-exclusion treatments. We conclude that leaf plasticity might help the trees to tolerate moderate drought but not to resist severe water stress.
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Affiliation(s)
| | - Amélie Roussel
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Jesús Rodríguez-Calcerrada
- Departamento de Sistemas y Recursos Naturales, ETSI Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid Ciudad Universitaria, Madrid, Spain
| | | | - Myriam Moreno
- Unité Ecologie des Forêts Méditerranéennes (UR629), INRAE Avignon Cedex 9, Domaine Saint Paul, Site Agroparc, France
| | | | | | - Guillaume Simioni
- Unité Ecologie des Forêts Méditerranéennes (UR629), INRAE Avignon Cedex 9, Domaine Saint Paul, Site Agroparc, France
| | - Hervé Cochard
- PIAF, University Clermont-Auvergne, INRAE, Clermont-Ferrand, France
| | - Nicolas Martin-StPaul
- Unité Ecologie des Forêts Méditerranéennes (UR629), INRAE Avignon Cedex 9, Domaine Saint Paul, Site Agroparc, France
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12
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Benson MC, Miniat CF, Oishi AC, Denham SO, Domec JC, Johnson DM, Missik JE, Phillips RP, Wood JD, Novick KA. The xylem of anisohydric Quercus alba L. is more vulnerable to embolism than isohydric codominants. PLANT, CELL & ENVIRONMENT 2022; 45:329-346. [PMID: 34902165 DOI: 10.1111/pce.14244] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
The coordination of plant leaf water potential (ΨL ) regulation and xylem vulnerability to embolism is fundamental for understanding the tradeoffs between carbon uptake and risk of hydraulic damage. There is a general consensus that trees with vulnerable xylem more conservatively regulate ΨL than plants with resistant xylem. We evaluated if this paradigm applied to three important eastern US temperate tree species, Quercus alba L., Acer saccharum Marsh. and Liriodendron tulipifera L., by synthesizing 1600 ΨL observations, 122 xylem embolism curves and xylem anatomical measurements across 10 forests spanning pronounced hydroclimatological gradients and ages. We found that, unexpectedly, the species with the most vulnerable xylem (Q. alba) regulated ΨL less strictly than the other species. This relationship was found across all sites, such that coordination among traits was largely unaffected by climate and stand age. Quercus species are perceived to be among the most drought tolerant temperate US forest species; however, our results suggest their relatively loose ΨL regulation in response to hydrologic stress occurs with a substantial hydraulic cost that may expose them to novel risks in a more drought-prone future.
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Affiliation(s)
- Michael C Benson
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Chelcy F Miniat
- USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, North Carolina, USA
| | - Andrew C Oishi
- USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, North Carolina, USA
| | - Sander O Denham
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro, INRA UMR 1391 ISPA, Gradignan, France
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - Justine E Missik
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Richard P Phillips
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Jeffrey D Wood
- University of Missouri, School of Natural Resources, Columbia, Missouri, USA
| | - Kimberly A Novick
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
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13
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Huo J, Shi Y, Zhang H, Hu R, Huang L, Zhao Y, Zhang Z. More sensitive to drought of young tissues with weak water potential adjustment capacity in two desert shrubs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 790:148103. [PMID: 34111778 DOI: 10.1016/j.scitotenv.2021.148103] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
Water is the main limiting factor for survival and growth for desert plants, and plants can alleviate water deficits under drought by adjusting water potential (Ψ). However, the water potential adjustment capacity and water-sensitivity at the tissue level among shrub species remains unclear. The objective of this study was to evaluate water potential adjustment capacity and water-sensitivity of different tissues in Artemisia ordosica and Caragana korshinskii through calculating the water relation parameters from pressure-volume (P-V) curves. The present study found that the sensitivity coefficients, -1/β and -1/b, were gradually decreased with increasing degree of lignification in A. ordosica and C. korshinskii, suggesting that younger tissues with low lignification are more sensitive to water deficit. Additionally, the younger tissues with more negative osmotic potential at full turgor (Ψπ, sat), water potential at turgor loss point (Ψtlp), and lower the bulk modulus of elasticity (ε), the relative water deficit at turgor loss point (RWDtlp), apoplastic water fraction (AWF) and total hydraulic capacitance (Ctotal), which indicated that younger tissues have stronger turgor adjustment capacity compared to osmotic adjustment capacity and them were more easily lose water during times of decreased water potential because of higher cell wall elasticity and weaker water storage capacity. Collectively, the present study highlighted that younger tissues are more sensitive to drought due to their weaker water potential adjustment capacity and provided critical insight into water physiological mechanism or sensitivity of species to drought.
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Affiliation(s)
- Jianqiang Huo
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yafei Shi
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing, China
| | - Hongxia Zhang
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China
| | - Rui Hu
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China
| | - Lei Huang
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China
| | - Yang Zhao
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China.
| | - Zhishan Zhang
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China.
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14
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Martínez-Vilalta J, Santiago LS, Poyatos R, Badiella L, de Cáceres M, Aranda I, Delzon S, Vilagrosa A, Mencuccini M. Towards a statistically robust determination of minimum water potential and hydraulic risk in plants. THE NEW PHYTOLOGIST 2021; 232:404-417. [PMID: 34153132 DOI: 10.1111/nph.17571] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/14/2021] [Indexed: 05/12/2023]
Abstract
Minimum water potential (Ψmin ) is a key variable for characterizing dehydration tolerance and hydraulic safety margins (HSMs) in plants. Ψmin is usually estimated as the absolute minimum tissue Ψ experienced by a species, but this is problematic because sample extremes are affected by sample size and the underlying probability distribution. We compare alternative approaches to estimate Ψmin and assess the corresponding uncertainties and biases; propose statistically robust estimation methods based on extreme value theory (EVT); and assess the implications of our results for the characterization of hydraulic risk. Our results show that current estimates of Ψmin and HSMs are biased, as they are strongly affected by sample size. Because sampling effort is generally higher for species living in dry environments, the differences in current Ψmin estimates between these species and those living under milder conditions are partly artefactual. When this bias is corrected using EVT methods, resulting HSMs tend to increase substantially with resistance to embolism across species. Although data availability and representativeness remain the main challenges for proper determination of Ψmin , a closer look at Ψ distributions and the use of statistically robust methods to estimate Ψmin opens new ground for characterizing plant hydraulic risks.
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Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, E08193, Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, E08193, Spain
| | - Louis S Santiago
- Department of Botany & Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA, 92521, USA
| | - Rafael Poyatos
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, E08193, Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, E08193, Spain
| | - Llorenç Badiella
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, E08193, Spain
| | - Miquel de Cáceres
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, E08193, Spain
- Joint Research Unit CTFC - AGROTECNIO, Solsona, 25280, Spain
| | - Ismael Aranda
- Centro de Investigación Forestal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Carretera Coruña Km 7.5, Madrid, E-28040, Spain
| | | | - Alberto Vilagrosa
- CEAM Foundation, Joint Research Unit University of Alicante-CEAM, Dept Ecology, University of Alicante, Carr. de San Vicente del Raspeig, PO Box 99, Alicante, 03080, Spain
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, E08193, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, 08010, Spain
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15
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Yao GQ, Nie ZF, Zeng YY, Waseem M, Hasan MM, Tian XQ, Liao ZQ, Siddique KHM, Fang XW. A clear trade-off between leaf hydraulic efficiency and safety in an aridland shrub during regrowth. PLANT, CELL & ENVIRONMENT 2021; 44:3347-3357. [PMID: 34327717 DOI: 10.1111/pce.14156] [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: 04/20/2021] [Revised: 07/16/2021] [Accepted: 07/18/2021] [Indexed: 06/13/2023]
Abstract
It has been suggested that a trade-off between hydraulic efficiency and safety is related to drought adaptation across species. However, whether leaf hydraulic efficiency is sacrificed for safety during woody resprout regrowth after crown removal is not well understood. We measured leaf water potential (ψleaf ) at predawn (ψpd ) and midday (ψmid ), leaf maximum hydraulic conductance (Kleaf-max ), ψleaf at induction 50% loss of Kleaf-max (Kleaf P50 ), leaf area-specific whole-plant hydraulic conductance (LSC), leaf vein structure and turgor loss point (πtlp ) in 1- to 13-year-old resprouts of the aridland shrub (Caragana korshinskii). ψpd was similar, ψmid and Kleaf P50 became more negative, and Kleaf-max decreased in resprouts with the increasing age; thus, leaf hydraulic efficiency clearly traded off against safety. The difference between ψmid and Kleaf P50 , leaf hydraulic safety margin, increased gradually with increasing resprout age. More negative ψmid and Kleaf P50 were closely related to decreasing LSC and more negative πtlp , respectively, and the decreasing Kleaf-max arose from the lower minor vein density and the narrower midrib xylem vessels. Our results showed that a clear trade-off between leaf hydraulic efficiency and safety helps C. korshinskii resprouts adapt to increasing water stress as they approach final size.
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Affiliation(s)
- Guang-Qian Yao
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
| | - Zheng-Fei Nie
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
| | - Yuan-Yuan Zeng
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
| | - Muhammad Waseem
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
| | - Md Mahadi Hasan
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
| | - Xue-Qian Tian
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
| | - Zhong-Qiang Liao
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
| | - Kadambot H M Siddique
- The UWA Institute of Agriculture and UWA School of Agriculture and Environment, The University of Western Australia, Perth, Western Australia, Australia
| | - Xiang-Wen Fang
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
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16
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González-Rebeles G, Terrazas T, Méndez-Alonzo R, Paz H, Brodribb TJ, Tinoco-Ojanguren C. Leaf water relations reflect canopy phenology rather than leaf life span in Sonoran Desert trees. TREE PHYSIOLOGY 2021; 41:1627-1640. [PMID: 33611521 DOI: 10.1093/treephys/tpab032] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
Plants from arid environments display covarying traits to survive or resist drought. Plant drought resistance and ability to survive long periods of low soil water availability should involve leaf phenology coordination with leaf and stem functional traits related to water status. This study tested correlations between phenology and functional traits involved in plant water status regulation in 10 Sonoran Desert tree species with contrasting phenology. Species seasonal variation in plant water status was defined by calculating their relative positions along the iso/anisohydric regulation continuum based on their hydroscape areas (HA)-a metric derived from the relationship between predawn and midday water potentials-and stomatal and hydraulic traits. Additionally, functional traits associated with plant water status regulation, including lamina vessel hydraulic diameter (DHL), stem-specific density (SSD) and leaf mass per area (LMA) were quantified per species. To characterize leaf phenology, leaf longevity (LL) and canopy foliage duration (FD) were determined. Hydroscape area was strongly correlated with FD but not with leaf longevity (LL); HA was significantly associated with SSD and leaf hydraulic traits (DHL, LMA) but not with stem hydraulic traits (vulnerability index, relative conductivity); and FD was strongly correlated with LMA and SSD. Leaf physiological characteristics affected leaf phenology when it was described as canopy FD better than when described as LL. Stem and leaf structure and hydraulic functions were not only relevant for categorizing species along the iso/anisohydric continuum but also allowed identifying different strategies of desert trees within the 'fast-slow' plant economics spectrum. The results in this study pinpoint the set of evolutionary pressures that shape the Sonoran Desert Scrub physiognomy.
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Affiliation(s)
- Georgina González-Rebeles
- Instituto de Ecología, Universidad Nacional Autónoma de México, Campus Hermosillo, Luis Donaldo Colosio s/n, 83250 Los Arcos, Hermosillo, Sonora, México
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México Unidad de Posgrado, Circuito de Posgrados, Ciudad Universitaria 04510 Coyoacán, Ciudad de México, México
| | - Teresa Terrazas
- Instituto de Biología, Universidad Nacional Autónoma de México, Circuito Zona Deportiva S/N, Ciudad Universitaria, 04510 Coyoacán, Ciudad de México, México
| | - Rodrigo Méndez-Alonzo
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada, Carretera Ensenada-Tijuana No. 3918, 22860 Zona Playitas, Ensenada, Baja California, México
| | - Horacio Paz
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, 58190 Ex Hacienda de San José de la Huerta, Morelia, Michoacán, México
| | - Tim J Brodribb
- Department of Plant Sciences, University of Tasmania, 7005 Sandy Bay, Hobart, Tasmania, Australia
| | - Clara Tinoco-Ojanguren
- Instituto de Ecología, Universidad Nacional Autónoma de México, Campus Hermosillo, Luis Donaldo Colosio s/n, 83250 Los Arcos, Hermosillo, Sonora, México
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17
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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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18
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Aranda I, Cadahía E, Fernández de Simón B. Specific leaf metabolic changes that underlie adjustment of osmotic potential in response to drought by four Quercus species. TREE PHYSIOLOGY 2021; 41:728-743. [PMID: 33231684 DOI: 10.1093/treephys/tpaa157] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/11/2020] [Indexed: 05/14/2023]
Abstract
Osmotic adjustment is almost ubiquitous as a mechanism of response to drought in many forest species. Recognized as an important mechanism of increasing turgor under water stress, the metabolic basis for osmotic adjustment has been described in only a few species. We set an experiment with four species of the genus Quercus ranked according to drought tolerance and leaf habit from evergreen to broad-leaved deciduous. A cycle of watering deprivation was imposed on seedlings, resulting in well-watered (WW) and water-stressed (WS) treatments, and their water relations were assessed from pressure-volume curves. Leaf predawn water potential (Ψpd) significantly decreased in WS seedlings, which was followed by a drop in leaf osmotic potential at full turgor (Ψπ100). The lowest values of Ψπ100 followed the ranking of decreasing drought tolerance: Quercus ilex L. < Quercus faginea Lam. < Quercus pyrenaica Willd. < Quercus petraea Matt. Liebl. The leaf osmotic potential at the turgor loss point (ΨTLP) followed the same pattern as Ψπ100 across species and treatments. The pool of carbohydrates, some organic acids and cyclitols were the main osmolytes explaining osmotic potential across species, likewise to the osmotic adjustment assessed from the decrease in leaf Ψπ100 between WW and WS seedlings. Amino acids were very responsive to WS, particularly γ-aminobutyric acid in Q. pyrenaica, but made a relatively minor contribution to osmotic potential compared with other groups of compounds. In contrast, the cyclitol proto-quercitol made a prominent contribution to the changes in osmotic potential regardless of watering treatment or species. However, different metabolites, such as quinic acid, played a more important role in osmotic adjustment in Q. ilex, distinguishing it from the other species studied. In conclusion, while osmotic adjustment was present in all four Quercus species, the molecular processes underpinning this response differed according to their phylogenetic history and specific ecology.
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Affiliation(s)
- Ismael Aranda
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación Forestal, Carretera Coruña Km 7.5, E-28040 Madrid, Spain
- INAGEA, Instituto de Investigaciones Agroambientales y de Economía del Agua, 07122 Palma de Mallorca, Spain
| | - Estrella Cadahía
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación Forestal, Carretera Coruña Km 7.5, E-28040 Madrid, Spain
| | - Brígida Fernández de Simón
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación Forestal, Carretera Coruña Km 7.5, E-28040 Madrid, Spain
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19
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Peltier DMP, Guo J, Nguyen P, Bangs M, Gear L, Wilson M, Jefferys S, Samuels-Crow K, Yocom LL, Liu Y, Fell MK, Auty D, Schwalm C, Anderegg WRL, Koch GW, Litvak ME, Ogle K. Temporal controls on crown nonstructural carbohydrates in southwestern US tree species. TREE PHYSIOLOGY 2021; 41:388-402. [PMID: 33147630 DOI: 10.1093/treephys/tpaa149] [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: 07/28/2020] [Accepted: 10/29/2020] [Indexed: 06/11/2023]
Abstract
In trees, large uncertainties remain in how nonstructural carbohydrates (NSCs) respond to variation in water availability in natural, intact ecosystems. Variation in NSC pools reflects temporal fluctuations in supply and demand, as well as physiological coordination across tree organs in ways that differ across species and NSC fractions (e.g., soluble sugars vs starch). Using landscape-scale crown (leaves and twigs) NSC concentration measurements in three foundation tree species (Populus tremuloides, Pinus edulis, Juniperus osteosperma), we evaluated in situ, seasonal variation in NSC responses to moisture stress on three timescales: short-term (via predawn water potential), seasonal (via leaf δ13C) and annual (via current year's ring width index). Crown NSC responses to moisture stress appeared to depend on hydraulic strategy, where J. osteosperma appears to regulate osmotic potentials (via higher sugar concentrations), P. edulis NSC responses suggest respiratory depletion and P. tremuloides responses were consistent with direct sink limitations. We also show that overly simplistic models can mask seasonal and tissue variation in NSC responses, as well as strong interactions among moisture stress at different timescales. In general, our results suggest large seasonal variation in crown NSC concentrations reflecting the multiple cofunctions of NSCs in plant tissues, including storage, growth and osmotic regulation of hydraulically vulnerable leaves. We emphasize that crown NSC pool size cannot be viewed as a simple physiological metric of stress; in situ NSC dynamics are complex, varying temporally, across species, among NSC fractions and among tissue types.
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Affiliation(s)
- Drew M P Peltier
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Jessica Guo
- Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, USA
| | - Phiyen Nguyen
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Michael Bangs
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Linnea Gear
- Department of Chemistry and Biochemistry, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Michelle Wilson
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Stacy Jefferys
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Kimberly Samuels-Crow
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Larissa L Yocom
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Yao Liu
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Michael K Fell
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - David Auty
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Christopher Schwalm
- Woods Hole Research Center, Falmouth, MA 02540, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - George W Koch
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Marcy E Litvak
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Kiona Ogle
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
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20
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Jiang P, Meinzer FC, Fu X, Kou L, Dai X, Wang H. Trade-offs between xylem water and carbohydrate storage among 24 coexisting subtropical understory shrub species spanning a spectrum of isohydry. TREE PHYSIOLOGY 2021; 41:403-415. [PMID: 33079181 DOI: 10.1093/treephys/tpaa138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Hydraulic capacitance and carbohydrate storage are two drought adaptation strategies of woody angiosperms. However, we currently lack information on their associations and how they are associated with species' degree of isohydry. We measured total stem xylem nonstructural carbohydrate (NSC) concentration in the dry and wet seasons, xylem hydraulic capacitance, native leaf water potentials, pressure-volume curve parameters and photosynthetic performance in 24 woody understory species differing in their degree of isohydry. We found a trade-off between xylem water and carbohydrate storage both in storage capacitance and along a spectrum of isohydry. Species with higher hydraulic capacitance had lower native NSC storage. The less isohydric species tended to show greater NSC depletion in the dry season and have more drought-tolerant leaves. In contrast, the more isohydric species had higher hydraulic capacitance, which may enhance their drought avoidance capacity. In these species, leaf flushing in the wet season and higher photosynthetic rates in the dry season resulted in accumulation rather than depletion of NSC in the dry season. Our results provide new insights into the mechanisms through which xylem storage functions determine co-occurring species' drought adaptation strategies and improve our capacity to predict community assembly processes under drought.
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Affiliation(s)
- Peipei Jiang
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
- Key Laboratory of Plant Stress Research, College of Life Science, Shandong Normal University, Jinan 250014, China
| | - Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, USA
| | - Xiaoli Fu
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Liang Kou
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaoqin Dai
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Huimin Wang
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
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Harding SA, Frost CJ, Tsai CJ. Defoliation-induced compensatory transpiration is compromised in SUT4-RNAi Populus. PLANT DIRECT 2020; 4:e00268. [PMID: 33015535 PMCID: PMC7522500 DOI: 10.1002/pld3.268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 07/13/2020] [Accepted: 08/23/2020] [Indexed: 06/11/2023]
Abstract
The tonoplast sucrose transporter PtaSUT4 is well expressed in leaves of Populus tremula × Populus alba (INRA 717-IB4), and its inhibition by RNA-interference (RNAi) alters leaf sucrose homeostasis. Whether sucrose partitioning between the vacuole and the cytosol is modulated by PtaSUT4 for specific physiological outcomes in Populus remains unexplored. In this study, partial defoliation was used to elicit compensatory increases in photosynthesis and transpiration by the remaining leaves in greenhouse-grown poplar. Water uptake, leaf gas exchange properties, growth and nonstructural carbohydrate abundance in source and sink organs were then compared between wild-type and SUT4-RNAi lines. Partial defoliation increased maximum photosynthesis rates similarly in all lines. There was no indication that source leaf sugar levels changed differently between wild-type and RNAi plants following partial defoliation. Sink levels of hexose (glucose and fructose) and starch decreased similarly in all lines. Interestingly, plant water uptake after partial defoliation was not as well sustained in RNAi as in wild-type plants. While the compensatory increase in photosynthesis was similar between genotypes, leaf transpiration increased less robustly in RNAi than wild-type plants. SUT4-RNAi and wild-type source leaves differed constitutively in their bulk modulus of elasticity, a measure of leaf turgor, and storage water capacitance. The data demonstrate that reduced sucrose partitioning due to PtaSUT4-RNAi altered turgor control and compensatory transpiration capacity more strikingly than photosynthesis and sugar export. The results are consistent with the interpretation that SUT4 may control vacuolar turgor independently of sink carbon provisioning.
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Affiliation(s)
- Scott A Harding
- Warnell School of Forestry and Natural Resources Department of Genetics and Department of Plant Biology University of Georgia Athens GA USA
| | - Christopher J Frost
- Warnell School of Forestry and Natural Resources Department of Genetics and Department of Plant Biology University of Georgia Athens GA USA
- Present address: BIO5 Institute University of Arizona Tucson AZ 85719 USA
| | - Chung-Jui Tsai
- Warnell School of Forestry and Natural Resources Department of Genetics and Department of Plant Biology University of Georgia Athens GA USA
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Alvarez-Maldini C, Acevedo M, Dumroese RK, González M, Cartes E. Intraspecific Variation in Drought Response of Three Populations of Cryptocarya alba and Persea lingue, Two Native Species From Mediterranean Central Chile. FRONTIERS IN PLANT SCIENCE 2020; 11:1042. [PMID: 32765551 PMCID: PMC7378861 DOI: 10.3389/fpls.2020.01042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/24/2020] [Indexed: 05/24/2023]
Abstract
An increase in the severity of drought events on Mediterranean climates highlights the need of using plant material adapted to drought during restoration efforts. Thus, we investigated between-population morpho-physiological differences in Cryptocarya alba and Persea lingue, two native species from Mediterranean central Chile, for traits that could effectively discriminate population performance in response to water restriction (WR) testing. Three populations from each species were subjected to WR treatment and physiological, morphological, and growth parameters were assessed at the beginning and at the end of the experiment. In C. alba, the most xeric population displayed smaller plants with mesophyllous leaves and lower photosynthetic rates indicating a resource saving strategy. Moreover, the xeric population performed better during WR than the most mesic populations, exhibiting higher water use efficiency (iWUE) and maintenance of growth rates. All C. alba populations responded equally to WR in terms of morphology and biomass partitioning. In contrast, differences among P. lingue populations were subtle at the morpho-physiological level with no apparent relation to provenance environmental conditions, and no morphological traits were affected by WR. However, in response to WR application, the most mesic population was, as observed through reduction in relative growth rates, more affected than xeric populations. We attribute such discrete differences between P. lingue provenances to the lower distributional range of selected populations. Our results show that relative growth rates in both species, and iWUE only in C. alba, exhibited population specific responses upon WR imposition; these results correspond with the environmental conditions found at the origin of each populations. Both traits could further assist in the selection of populations for restoration according to their response to water stress.
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Affiliation(s)
- Carolina Alvarez-Maldini
- Institute of Agri-food, Animal and Environmental Sciences (ICA3), Universidad de O Higgins, San Fernando, Chile
| | - Manuel Acevedo
- Centro Tecnológico de la Planta Forestal, Instituto Forestal, San Pedro de la Paz, Chile
| | - R. Kasten Dumroese
- Rocky Mountain Research Station, US Department of Agriculture, Forest Service, Moscow, ID, United States
| | - Marta González
- Centro Tecnológico de la Planta Forestal, Instituto Forestal, San Pedro de la Paz, Chile
| | - Eduardo Cartes
- Centro Tecnológico de la Planta Forestal, Instituto Forestal, San Pedro de la Paz, Chile
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Laughlin DC, Delzon S, Clearwater MJ, Bellingham PJ, McGlone MS, Richardson SJ. Climatic limits of temperate rainforest tree species are explained by xylem embolism resistance among angiosperms but not among conifers. THE NEW PHYTOLOGIST 2020; 226:727-740. [PMID: 31981422 DOI: 10.1111/nph.16448] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Hydraulic failure explains much of the increased rates of drought-induced tree mortality around the world, underlining the importance of understanding how species distributions are shaped by their vulnerability to embolism. Here we determined which physiological traits explain species climatic limits among temperate rainforest trees in a region where chronic water limitation is uncommon. We quantified the variation in stem embolism vulnerability and leaf turgor loss point among 55 temperate rainforest tree species in New Zealand and tested which traits were most strongly related to species climatic limits. Leaf turgor loss point and stem P50 (tension at which hydraulic conductance is at 50% of maximum) were uncorrelated. Stem P50 and hydraulic safety margin were the most strongly related physiological traits to climatic limits among angiosperms, but not among conifers. Morphological traits such as wood density and leaf dry matter content did not explain species climatic limits. Stem embolism resistance and leaf turgor loss point appear to have evolved independently. Embolism resistance is the most useful predictor of the climatic limits of angiosperm trees. High embolism resistance in the curiously overbuilt New Zealand conifers suggests that their xylem properties may be more closely related to growing slowly under nutrient limitation and to resistance to microbial decomposition.
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Affiliation(s)
- Daniel C Laughlin
- Department of Botany, University of Wyoming, Laramie, WY, 82071, USA
| | - Sylvain Delzon
- INRA, BIOGECO, University of Bordeaux, 33615, Pessac, France
| | | | - Peter J Bellingham
- Manaaki Whenua - Landcare Research, PO Box 69040, Lincoln, 7640, New Zealand
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Matthew S McGlone
- Manaaki Whenua - Landcare Research, PO Box 69040, Lincoln, 7640, New Zealand
| | - Sarah J Richardson
- Manaaki Whenua - Landcare Research, PO Box 69040, Lincoln, 7640, New Zealand
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Chacon AI, Baer A, Wheeler JK, Pittermann J. Two coastal Pacific evergreens, Arbutus menziesii, Pursh. and Quercus agrifolia, Née show little water stress during California's exceptional drought. PLoS One 2020; 15:e0230868. [PMID: 32240222 PMCID: PMC7117729 DOI: 10.1371/journal.pone.0230868] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 03/10/2020] [Indexed: 11/30/2022] Open
Abstract
California's coastal climate is characterized by rainy winters followed by a dry summer season that is supplemented by frequent fog. While rising temperatures and drought caused massive tree mortality in central California during the 2011–2015 extreme drought, dying trees were less common in the central coast region. We hypothesized that cooler, maritime-ameliorated temperatures reduced the effects of drought stress on coastal vegetation. To test this, weekly measurements of water potential and stomatal conductance were made on two coast evergreen tree species, Arbutus menziesii and Quercus agrifolia, throughout the summer 2014 dry season. Water potential remained generally constant during this period but stomatal conductance declined in both species as the dry season progressed. Species' resistance to embolism was determined using the centrifuge method, and showed Q. agrifolia to be more vulnerable to embolism than A. menziesii. The stem vulnerability curves were consistent with species' seasonal water relations as well as their anatomy; the ring-porous Q. agrifolia had substantially larger conduits than the diffuse-porous A. menziesii. Leaf turgor loss points differed significantly as did other pressure-volume parameters but these data were consistent with the trees' seasonal water relations. Overall, the two species appear to employ differing water use strategies; A. menziesii is more profligate in its water use, while Q. agrifolia is more conservative, with a narrower safety margin against drought-induced loss of xylem transport capacity. Despite the extended drought, these species exhibited neither branch die-back nor any obvious symptoms of pronounced water-stress during the study period, implying that the maritime climate of California's central coast may buffer the local vegetation against the severe effects of prolonged drought.
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Affiliation(s)
- Alexander I. Chacon
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, United States of America
| | - Alexander Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, United States of America
| | - James K. Wheeler
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, United States of America
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, United States of America
- * E-mail:
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Baer A, Wheeler JK, Pittermann J. Limited hydraulic adjustments drive the acclimation response of Pteridium aquilinum to variable light. ANNALS OF BOTANY 2020; 125:691-700. [PMID: 31956911 PMCID: PMC7102999 DOI: 10.1093/aob/mcaa006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/14/2020] [Indexed: 05/27/2023]
Abstract
BACKGROUND AND AIMS The success of invasive plants can be attributed to many traits including the ability to adapt to variable environmental conditions. Whether by adaptation, acclimation or phenotypic plasticity, these plants often increase their resource-use efficiency and, consequently, their fitness. The goal of this study was to examine the hydraulic and eco-physiological attributes of sun and shade populations of Pteridium aquilinum, a weedy fern, to determine whether the presence of vessels and other hydraulic attributes affects its success under a variety of light conditions. METHODS Hydraulic traits such as cavitation resistance, hydraulic conductivity, photosynthesis and water potential at turgor loss point were measured on fronds from sun and shade populations. Anatomical and structural traits such as conduit diameter and length, stomatal density and vein density were also recorded. Diurnal measures of leaf water potential and stomatal conductance complement these data. KEY RESULTS Gas exchange was nearly double in the sun plants, as was water-use efficiency, leaf-specific conductivity, and stomatal and vein density. This was largely achieved by a decrease in leaf area, coupled with higher xylem content. There was no significant difference in petiole cavitation resistance between the sun and shade leaves, nor in xylem-specific conductivity. Hydraulic conduit diameters were nearly equivalent in the two leaf types. CONCLUSIONS Shifts in leaf area and xylem content allow P. aquilinum to occupy habitats with full sun, and to adjust its physiology accordingly. High rates of photosynthesis explain in part the success of this fern in disturbed habitats, although no change was observed in intrinsic xylem qualities such as cavitation resistance or conduit length. This suggests that P. aquilinum is constrained by its fundamental body plan, in contrast to seed plants, which show greater capacity for hydraulic adjustment.
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Affiliation(s)
- Alex Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - James K Wheeler
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
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26
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Väänänen PJ, Osem Y, Cohen S, Grünzweig JM. Differential drought resistance strategies of co-existing woodland species enduring the long rainless Eastern Mediterranean summer. TREE PHYSIOLOGY 2020; 40:305-320. [PMID: 31860712 DOI: 10.1093/treephys/tpz130] [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: 07/01/2019] [Revised: 08/28/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
In anticipation of a drier climate and to project future changes in forest dynamics, it is imperative to understand species-specific differences in drought resistance. The objectives of this study were to form a comprehensive understanding of the drought resistance strategies adopted by Eastern Mediterranean woodland species, and to elaborate specific ecophysiological traits that can explain the observed variation in survival among these species. We examined leaf water potential (𝛹), gas exchange and stem hydraulics during 2-3 years in mature individuals of the key woody species Phillyrea latifolia L., Pistacia lentiscus L. and Quercus calliprinos Webb that co-exist in a dry woodland experiencing ~ 6 rainless summer months. As compared with the other two similarly functioning species, Phillyrea displayed considerably lower 𝛹 (minimum 𝛹 of -8.7 MPa in Phillyrea vs -4.2 MPa in Pistacia and Quercus), lower 𝛹 at stomatal closure and lower leaf turgor loss point (𝛹TLP ), but reduced hydraulic vulnerability and wider safety margins. Notably, Phillyrea allowed 𝛹 to drop below 𝛹TLP under severe drought, whereas the other two species maintained positive turgor. These results indicate that Phillyrea adopted a more anisohydric drought resistance strategy, while Pistacia and Quercus exhibited a more isohydric strategy and probably relied on deeper water reserves. Unlike the two relatively isohydric species, Phillyrea reached complete stomatal closure at the end of the dry summer. Despite assessing a large number of physiological traits, none of them could be directly related to tree mortality. Higher mortality was observed for Quercus than for the other two species, which may result from higher water consumption due to its 2.5-10 times larger crown volume. The observed patterns suggest that similar levels of drought resistance in terms of survival can be achieved via different drought resistance strategies. Conversely, similar resistance strategies in terms of isohydricity can lead to different levels of vulnerability to extreme drought.
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Affiliation(s)
- Päivi J Väänänen
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
- Department of Natural Resources, Agricultural Research Organization, Volcani Center, Bet-Dagan 50250, Israel
| | - Yagil Osem
- Department of Natural Resources, Agricultural Research Organization, Volcani Center, Bet-Dagan 50250, Israel
| | - Shabtai Cohen
- Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet-Dagan 50250, Israel
| | - José M Grünzweig
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
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27
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Godfrey JM, Riggio J, Orozco J, Guzmán-Delgado P, Chin ARO, Zwieniecki MA. Ray fractions and carbohydrate dynamics of tree species along a 2750 m elevation gradient indicate climate response, not spatial storage limitation. THE NEW PHYTOLOGIST 2020; 225:2314-2330. [PMID: 31808954 DOI: 10.1111/nph.16361] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/03/2019] [Indexed: 06/10/2023]
Abstract
Parenchyma cells in the xylem store nonstructural carbohydrates (NSC), providing reserves of energy that fuel woody perennials through periods of stress and/or limitations to photosynthesis. If the capacity for storage is subject to selection, then the fraction of wood occupied by living parenchyma should increase towards stressful environments. Ray parenchyma fraction (RPF) and seasonal NSC dynamics were quantified for 12 conifers and three oaks along a transect spanning warm dry foothills (500 m above sea level) to cold wet treeline (3250 m asl) in California's central Sierra Nevada. Mean RPF was lower for both conifer and oak species with warmer dryer ranges. RPF variability increased with elevation or in relation to associated climatic variables in conifers - treeline-dominant Pinus albicaulis had the lowest mean RPF measured (c. 3.7%), but the highest environmentally standardized variability index. Conifer RPF variability was explained by environment, increasing predominantly towards cooler wetter range edges. In oaks, NSC was explained by environment - values increasing for evergreen and decreasing for deciduous oaks with elevation. Lastly, all species surveyed appear to prioritize filling available RPF with sugar to achieve molarities that balance reasonable tensions over starch to maximize stored carbon. RPF responds to environment but is unlikely to spatially constrain NSC storage.
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Affiliation(s)
- Jessie M Godfrey
- Plant Sciences Department, University of California, Davis, CA, 95616, USA
| | - Jason Riggio
- Department of Wildlife, Fish, & Conservation Biology, University of California, Davis, CA, 95616, USA
| | - Jessica Orozco
- Plant Sciences Department, University of California, Davis, CA, 95616, USA
| | | | - Alana R O Chin
- Plant Sciences Department, University of California, Davis, CA, 95616, USA
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Ulrich DEM, Sevanto S, Peterson S, Ryan M, Dunbar J. Effects of Soil Microbes on Functional Traits of Loblolly Pine ( Pinus taeda) Seedling Families From Contrasting Climates. FRONTIERS IN PLANT SCIENCE 2020; 10:1643. [PMID: 31998333 PMCID: PMC6962191 DOI: 10.3389/fpls.2019.01643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 11/21/2019] [Indexed: 05/31/2023]
Abstract
Examining factors that influence seedling establishment is essential for predicting the impacts of climate change on tree species' distributions. Seedlings originating from contrasting climates differentially express functional traits related to water and nutrient uptake and drought resistance that reflect their climate of origin and influence their responses to drought. Soil microbes may improve seedling establishment because they can enhance water and nutrient uptake and drought resistance. However, the relative influence of soil microbes on the expression of these functional traits between seedling families or populations from contrasting climates is unknown. To determine if soil microbes may differentially alter functional traits to enhance water and nutrient uptake and drought resistance between dry and wet families, seeds of loblolly pine families from the driest and wettest ends of its geographic range (dry, wet) were planted in sterilized sand (controls) or in sterilized sand inoculated with a soil microbial community (inoculated). Functional traits related to seedling establishment (germination), water and nutrient uptake and C allocation (root:shoot biomass ratio, root exudate concentration, leaf C:N, leaf N isotope composition (δ15N)), and drought resistance (turgor loss point, leaf carbon isotope composition (δ13C)) were measured. Then, plants were exposed to a drought treatment and possible shifts in photosynthetic performance were monitored using chlorophyll fluorescence. Inoculated plants exhibited significantly greater germination than controls regardless of family. The inoculation treatment significantly increased root:shoot biomass ratio in the wet family but not in the dry family, suggesting soil microbes alter functional traits that improve water and nutrient uptake more so in a family originating from a wetter climate than in a family originating from a drier climate. Microbial effects on photosynthetic performance during drought also differed between families, as photosynthetic performance of the dry inoculated group declined fastest. Regardless of treatment, the dry family exhibited a greater root:shoot biomass ratio, root exudate concentration, and leaf δ15N than the wet family. This indicates that the dry family allocated more resources belowground than the wet and the two family may have used different sources of plant available N, which may be related to their contrasting climates of origin and influence their drought resistance. Examination of variation in impacts of soil microbes on seedling physiology improves efforts to enhance seedling establishment and beneficial plant-microbe interactions under climate change.
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Affiliation(s)
| | - Sanna Sevanto
- Earth and Environmental Sciences (EES-14), Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Samantha Peterson
- Earth and Environmental Sciences Department, New Mexico Institute of Mining and Technology, Socorro, NM, United States
| | - Max Ryan
- Earth and Environmental Sciences (EES-14), Los Alamos National Laboratory, Los Alamos, NM, United States
| | - John Dunbar
- Bioscience (B-11), Los Alamos National Laboratory, Los Alamos, NM, United States
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Aranda I, Cadahía E, Fernández de Simón B. Leaf ecophysiological and metabolic response in Quercus pyrenaica Willd seedlings to moderate drought under enriched CO 2 atmosphere. JOURNAL OF PLANT PHYSIOLOGY 2020; 244:153083. [PMID: 31812028 DOI: 10.1016/j.jplph.2019.153083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 07/01/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Impact of drought under enriched CO2 atmosphere on ecophysiological and leaf metabolic response of the sub-mediterranean Q. pyrenaica oak was studied. Seedlings growing in climate chamber were submitted to moderate drought (WS) and well-watered (WW) under ambient ([CO2]amb =400 ppm) or CO2 enriched atmosphere ([CO2]enr =800 ppm). The moderate drought endured by seedlings brought about a decrease in leaf gas exchange. However, net photosynthesis (Anet) was highly stimulated for plants at [CO2]enr. There was a decrease of the stomatal conductance to water vapour (gwv) in response to drought, and a subtle trend to be lower under [CO2]enr. The consequence of these changes was an important increase in the intrinsic leaf water use efficiency (WUEi). The electron transport rate (ETR) was almost a 20 percent higher in plants at [CO2]enr regardless drought endured by seedlings. The ETR/Anet was lower under [CO2]enr, pointing to a high capacity to maintain sinks for the uptake of extra carbon in the atmosphere. Impact of drought on the leaf metabolome, as a whole, was more evident than that from [CO2] enrichment of the atmosphere. Changes in pool of non-structural carbohydrates were observed mainly as a consequence of water deficit including increases of fructose, glucose, and proto-quercitol. Most of the metabolites affected by drought back up to levels of non-stressed seedlings after rewetting (recovery phase). It can be concluded that carbon uptake was stimulated by [CO2]enr, even under the stomatal closure that accompanied moderate drought. In the last, there was a positive effect in intrinsic water use efficiency (WUEi), which was much more improved under [CO2]enr. Leaf metabolome was little responsible and some few metabolites changed mainly in response to drought, with little differences between [CO2] growth conditions.
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Affiliation(s)
- Ismael Aranda
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, O.A., M.P. (INIA), Centro de Investigación Forestal, Carretera de A Coruña Km 7.5, 28040, Madrid, Spain; Instituto de Investigaciones Agroambientales y de Economía del Agua (INAGEA), Palma de Mallorca, Islas Baleares, Spain.
| | - Estrella Cadahía
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, O.A., M.P. (INIA), Centro de Investigación Forestal, Carretera de A Coruña Km 7.5, 28040, Madrid, Spain
| | - Brígida Fernández de Simón
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, O.A., M.P. (INIA), Centro de Investigación Forestal, Carretera de A Coruña Km 7.5, 28040, Madrid, Spain
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30
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Li Q, Wang N, Liu X, Liu S, Wang H, Zhang W, Wang R, Du N. Growth and physiological responses to successional water deficit and recovery in four warm-temperate woody species. PHYSIOLOGIA PLANTARUM 2019; 167:645-660. [PMID: 30637759 DOI: 10.1111/ppl.12922] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/20/2018] [Accepted: 01/08/2019] [Indexed: 05/19/2023]
Abstract
Plant responses to drought and their subsequent rehydration can provide evidence for forest dynamics within the context of climate change. In this study, the seedlings of two native species (Vitex negundo var. heterophylla, Quercus acutissima) and two exotic species (Robinia pseudoacacia, Amorpha fruticosa) to China were selected in a greenhouse experiment. The gas exchange, stem hydraulic parameters, plant osmoprotectant contents and antioxidant activities of the seedlings that were subjected to sustained drought and rehydration (test group) as well as those of well-irrigated seedlings (control group) were measured. The two native species exhibited a greater degree of isohydry with drought because they limited the stomatal opening timely from the onset of the drought. However, the two exotic species showed a more 'water spender'-like strategy with R. pseudoacacia showing anisohydric responses and A. fruticosa showing isohydrodynamic responses to drought. Severe drought significantly decreased the leaf gas exchange rates and hydraulic properties, whereas the instantaneous water use efficiency and osmoprotectant contents increased markedly. Most of the physiological parameters recovered rapidly after mild drought rehydration, but the water potential and/or supply of nonstructural carbohydrates did not recover after severe drought rehydration. The results demonstrate that the xylem hydraulic conductivity and shoot water potential jointly play a crucial role in the drought recovery of woody plants. In brief, the native species may play a dominant role in the future in warm-temperate forests because they employ a better balance between carbon gain and water loss than the alien species under extreme drought conditions.
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Affiliation(s)
- Qiang Li
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, 266237, China
| | - Ning Wang
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, 266237, China
| | - Xiao Liu
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, 266237, China
| | - Shuna Liu
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, 266237, China
| | - Hui Wang
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, 266237, China
| | - Wenxin Zhang
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, 266237, China
| | - Renqing Wang
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, 266237, China
| | - Ning Du
- Institute of Ecology and Biodiversity, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, Shandong University, Qingdao, 266237, China
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31
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Berry ZC, Espejel X, Williams-Linera G, Asbjornsen H. Linking coordinated hydraulic traits to drought and recovery responses in a tropical montane cloud forest. AMERICAN JOURNAL OF BOTANY 2019; 106:1316-1326. [PMID: 31518000 DOI: 10.1002/ajb2.1356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Understanding plant hydraulic functioning and water balance during drought has become key in predicting species survival and recovery. However, there are few insightful studies that couple physiological and morphological attributes for many ecosystems, such as the vulnerable Tropical Montane Cloud Forests (TMCF). In this study, we evaluated drought resistance and recovery for saplings for five tree species spanning deciduous to evergreen habits from a Mexican TMCF. METHODS In drought simulations, water was withheld until plants reached species-specific P50 or P88 values (pressures required to induce a 50 or 88% loss in hydraulic conductivity), then they were rewatered. Drought resistance was considered within the isohydric-anisohydric framework and compared to leaf gas exchange, water status, pressure-volume curves, specific leaf area, and stomatal density. RESULTS The TMCF species closed stomata well before significant losses in hydraulic conductivity (isohydric). Yet, despite the coordination of these traits, the traits were not useful for predicting the time needed for the species to reach critical hydraulic thresholds. Instead, maximum photosynthetic rates explained these times, reinforcing the linkage between hydraulic and carbon dynamics. Despite their varying hydraulic conductivities, stomatal responses, and times to hydraulic thresholds, 58 of the 60 study plants recovered after the rewatering. The recovery of photosynthesis and stomatal conductance can be explained by the P50 values and isohydry. CONCLUSIONS This study raises new questions surrounding drought management strategies, recovery processes, and how lethal thresholds are defined. Further studies need to consider the role of water and carbon balance in allowing for both survival and recovery from drought.
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Affiliation(s)
- Z Carter Berry
- Schmid College of Science and Technology, Chapman University, Orange, CA, 92866, USA
| | - Ximena Espejel
- Instituto de Ecología, A.C., Carretera Antigua a Coatepec 351, Xalapa, Veracruz, 91070, México
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Zhu SD, Li RH, He PC, Siddiq Z, Cao KF, Ye Q. Large branch and leaf hydraulic safety margins in subtropical evergreen broadleaved forest. TREE PHYSIOLOGY 2019; 39:1405-1415. [PMID: 30901055 DOI: 10.1093/treephys/tpz028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 02/21/2019] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
As a global biodiversity hotspot, the subtropical evergreen broadleaved forest (SEBF) in southern China is strongly influenced by the humid monsoon climate, with distinct hot-wet and cool-dry seasons. However, the hydraulic strategies of this forest are not well understood. Branch and leaf hydraulic safety margins (HSMbranch and HSMleaf, respectively), as well as seasonal changes in predawn and midday leaf water potential (Ψpd and Ψmd), stomatal conductance (Gs), leaf to sapwood area ratio (AL/AS) and turgor loss point (Ψtlp), were examined for woody species in a mature SEBF. For comparison, we compiled these traits of tropical dry forests (TDFs) and Mediterranean-type woodlands (MWs) from the literature because they experience a hot-dry season. We found that on average, SEBF showed larger HSMbranch and HSMleaf than TDF and MW. During the dry season, TDF and MW species displayed a significant decrease in Ψpd and Ψmd. However, SEBF species showed a slight decrease in Ψpd but an increase in Ψmd. Similar to TDF and MW species, Gs was substantially lower in the dry season for SEBF species, but this might be primarily because of the low atmospheric temperature (low vapor pressure deficit). On the other hand, AL/AS and Ψtlp were not significant different between seasons for any SEBF species. Most SEBF species had leaves that were more resistant to cavitation than branches. Additionally, species with stronger leaf-to-branch vulnerability segmentation tended to have smaller HSMleaf but larger HSMbranch. Our results suggest that SEBF is at low hydraulic risk under the current climate.
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Affiliation(s)
- Shi-Dan Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Daxuedong Road, Xixiangtang District, Nanning, Guangxi, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Daxuedong Road, Xixiangtang District, Nanning, Guangxi, China
| | - Rong-Hua Li
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road, Tianhe District, Guangzhou, Guangdong, China
| | - Peng-Cheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road, Tianhe District, Guangzhou, Guangdong, China
| | - Zafar Siddiq
- Department of Botany, Government College University, Katchery Road, Lahore, Pakistan
| | - Kun-Fang Cao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Daxuedong Road, Xixiangtang District, Nanning, Guangxi, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Daxuedong Road, Xixiangtang District, Nanning, Guangxi, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road, Tianhe District, Guangzhou, Guangdong, China
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33
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Condo TK, Reinhardt K. Large variation in branch and branch-tip hydraulic functional traits in Douglas-fir (Pseudotsuga menziesii) approaching lower treeline. TREE PHYSIOLOGY 2019; 39:1461-1472. [PMID: 31135912 DOI: 10.1093/treephys/tpz058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/29/2019] [Accepted: 05/13/2019] [Indexed: 06/09/2023]
Abstract
Few studies have quantified intraspecific variation of hydraulic functional traits in conifers across elevation gradients that include range boundaries. In the Intermountain West, USA, the lower elevational limit of forests (lower treeline) is generally assumed to be caused by water limitations to growth and water relations, yet few studies directly show this. To test this assumption, we measured changes in a suite of traits that characterize drought tolerance such as drought-induced hydraulic vulnerability, hydraulic transport capacity and morphological traits in branch tips and branches of Douglas-fir (Pseudotsuga menziesii var. glauca (Mirb.) Franco) along a 400-m elevation gradient in southeastern Idaho that included lower treeline. As elevation decreased, vulnerability to hydraulic dysfunction and maximum conductivity both decreased in branches; some hydraulic safety-efficiency trade-offs were evident. In branch tips, the water potential at the turgor loss point decreased, while maximum conductance increased with decreasing elevation, highlighting that branch-tip-level responses to less moisture availability accompanied by warmer temperatures might not be coordinated with branch responses. As the range boundary was approached, we did not observe non-linear changes in parameters among sites or increased variance within sites, which current ecological hypotheses on range limits suggest. Our results indicate that there is substantial plasticity in hydraulic functional traits in branch tips and branches of Douglas-fir, although the direction of the trends along the elevation gradient sometimes differed between organs. Such plasticity may mitigate the negative impacts of future drought on Douglas-fir productivity, slowing shifts in its range that are expected to occur with climate change.
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Affiliation(s)
- Theresa K Condo
- Department of Biological Sciences, Idaho State University, 921 S 8th Ave., Stop 8007, Pocatello, ID 83209, USA
| | - Keith Reinhardt
- Department of Biological Sciences, Idaho State University, 921 S 8th Ave., Stop 8007, Pocatello, ID 83209, USA
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Martinez-Vilalta J, Anderegg WRL, Sapes G, Sala A. Greater focus on water pools may improve our ability to understand and anticipate drought-induced mortality in plants. THE NEW PHYTOLOGIST 2019; 223:22-32. [PMID: 30560995 DOI: 10.1111/nph.15644] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/06/2018] [Indexed: 05/23/2023]
Abstract
Drought-induced tree mortality has major impacts on ecosystem carbon and water cycles, and is expected to increase in forests across the globe with climate change. A large body of research in the past decade has advanced our understanding of plant water and carbon relations under drought. However, despite intense research, we still lack generalizable, cross-scale indicators of mortality risk. In this Viewpoint, we propose that a more explicit consideration of water pools could improve our ability to monitor and anticipate mortality risk. Specifically, we focus on the relative water content (RWC), a classic metric in plant water relations, as a potential indicator of mortality risk that is physiologically relevant and integrates different aspects related to hydraulics, stomatal responses and carbon economy under drought. Measures of plant water content are likely to have a strong mechanistic link with mortality and to be integrative, threshold-prone and relatively easy to measure and monitor at large spatial scales, and may complement current mortality metrics based on water potential, loss of hydraulic conductivity and nonstructural carbohydrates. We discuss some of the potential advantages and limitations of these metrics to improve our capacity to monitor and predict drought-induced tree mortality.
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Affiliation(s)
- Jordi Martinez-Vilalta
- CREAF, Cerdanyola del Valles, 08193, Barcelona, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Valles, 08193, Barcelona, Spain
| | | | - Gerard Sapes
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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35
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Li X, Blackman CJ, Choat B, Rymer PD, Medlyn BE, Tissue DT. Drought tolerance traits do not vary across sites differing in water availability in Banksia serrata (Proteaceae). FUNCTIONAL PLANT BIOLOGY : FPB 2019; 46:624-633. [PMID: 30961787 DOI: 10.1071/fp18238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 02/23/2019] [Indexed: 06/09/2023]
Abstract
Interspecific variation in plant hydraulic traits plays a major role in shaping species distributions across climates, yet variation within species is poorly understood. Here we report on intraspecific variation of hydraulic traits in Banksia serrata (L.f.) sampled from three sites characterised by contrasting climates (warm-wet, warm-dry and cool-wet). Hydraulic characteristics including vulnerability to embolism, hydraulic conductance, pressure-volume traits and key morphological traits were measured. Vulnerability to embolism in leaf and stem, defined by the water potential inducing 50 and 88% loss of hydraulic conductivity (P50 and P88 respectively), did not differ across sites. However, plants from the warm-dry environment exhibited higher stem conductivity (Ks) than the cool-wet environment. Leaf turgor loss point (TLP) did not vary among sites, but warm-dry site plants showed lower leaf capacitance (C*FT) and higher modulus of elasticity (ε) than the other two sites. Plants from the cool-wet site had lower specific leaf area (SLA) and plants from the warm-dry site had lower sapwood density (WD). Overall, key hydraulic traits were generally conserved across populations despite differences in mean site water availability, and the safety-efficiency trade-off was absent in this species. These results suggest that B. serrata has limited ability to adjust hydraulic architecture in response to environmental change and thus may be susceptible to climate change-type drought stress.
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Affiliation(s)
- Ximeng Li
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Chris J Blackman
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Paul D Rymer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia; and Corresponding author.
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36
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Dharmappa PM, Doddaraju P, Malagondanahalli MV, Rangappa RB, Mallikarjuna NM, Rajendrareddy SH, Ramanjinappa R, Mavinahalli RP, Prasad TG, Udayakumar M, Sheshshayee SM. Introgression of Root and Water Use Efficiency Traits Enhances Water Productivity: An Evidence for Physiological Breeding in Rice (Oryza sativa L.). RICE (NEW YORK, N.Y.) 2019; 12:14. [PMID: 30847616 PMCID: PMC6405788 DOI: 10.1186/s12284-019-0268-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 02/11/2019] [Indexed: 05/29/2023]
Abstract
BACKGROUND Semi-irrigated aerobic cultivation of rice has been suggested as a potential water saving agronomy. However, suitable cultivars are needed in order to sustain yield levels. An introgression of water mining and water use efficiency (WUE) traits is the most appropriate strategy for a comprehensive genetic enhancement to develop such rice cultivars. RESULTS We report a novel strategy of phenotyping and marker-assisted backcross breeding to introgress water mining (root) and water use efficiency (WUE) traits into a popular high yielding cultivar, IR-64. Trait donor genotypes for root (AC-39020) and WUE (IET-16348) were crossed separately and the resultant F1s were inter-mated to generate double cross F1s (DCF1). Progenies of three generations of backcross followed by selfing were charatcerised for target phenotype and genome integration. A set of 260 trait introgressed lines were identified. Root weight and root length of TILs were 53% and 23.5% higher, while Δ13C was 2.85‰ lower indicating a significant increase in WUE over IR-64. Five best TILs selected from BC3F3 generation showed 52% and 63% increase in yield over IR-64 under 100% and 60% FC, respectively. The trait introgressed lines resembled IR64 with more than 97% of genome recovered with a significant yield advantage under semi-irrigated aerobic conditions The study validated markers identified earlier by association mapping. CONCLUSION Introgression of root and WUE into IR64, resulted in an excellent yield advantage even when cultivated under semi-irrigated aerobic condition. The study provided a proof-of-concept that maintaining leaf turgor and carbon metabolism results in improved adaptation to water limited conditions and sustains productivity. A marker based multi-parent backcross breeding is an appropriate approach for trait introgression. The trait introgressed lines developed can be effectively used in future crop improvement programs as donor lines for both root and WUE.
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Affiliation(s)
- Prathibha M. Dharmappa
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
| | - Pushpa Doddaraju
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
| | | | - Raju B. Rangappa
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
- Present address- Department of Agronomy Kansas State University, Kansas, USA
| | - N. M. Mallikarjuna
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
| | - Sowmya H. Rajendrareddy
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
| | - Ramachandra Ramanjinappa
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
- Present address: Assistant Professor, Department of Biotechnology, Reva University, Bengaluru, India
| | | | - Trichy Ganesh Prasad
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
| | - Makarla Udayakumar
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
| | - Sreeman M. Sheshshayee
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru, 560065 India
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37
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Ulrich DEM, Sevanto S, Ryan M, Albright MBN, Johansen RB, Dunbar JM. Plant-microbe interactions before drought influence plant physiological responses to subsequent severe drought. Sci Rep 2019; 9:249. [PMID: 30670745 PMCID: PMC6342978 DOI: 10.1038/s41598-018-36971-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 11/29/2018] [Indexed: 12/20/2022] Open
Abstract
We examined the effect of soil microbial communities on plant physiological responses to drought. Bouteloua gracilis seeds were planted in sterilized sand with (inoculated) and without (controls) soil microbial communities. After substantial growth, drought was imposed by completely withholding water. Before soil moisture declined to zero, inoculated plants germinated faster, were significantly taller, and maintained greater soil moisture than controls. The greater soil moisture of the inoculated plants allowed greater photosynthesis but also induced lower tissue drought tolerance (as indicated by turgor loss point) compared to controls. The inoculated plants were more susceptible to severe drought compared to control plants as indicated by significantly lower mean stomatal conductance, as well as marginally significantly greater mean wilting score, for the entire severe drought period after soil moisture declined to zero. Inoculated plants exhibited enhanced growth and photosynthesis and dampened drought stress over short timescales, but also increased susceptibility to drought over long timescales. This work demonstrates (1) an unexpected insight that microbes can have positive initial effects on plant performance, but negative impacts on plant performance during severe drought, and (2) that microbially altered effects on plant function during well-watered and moderate drought conditions can influence plant function under subsequent severe drought.
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Affiliation(s)
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Max Ryan
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | - Renee B Johansen
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - John M Dunbar
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, USA
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38
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Extending the osmometer method for assessing drought tolerance in herbaceous species. Oecologia 2019; 189:353-363. [PMID: 30627784 DOI: 10.1007/s00442-019-04336-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 01/02/2019] [Indexed: 10/27/2022]
Abstract
Community-scale surveys of plant drought tolerance are essential for understanding semi-arid ecosystems and community responses to climate change. Thus, there is a need for an accurate and rapid methodology for assessing drought tolerance strategies across plant functional types. The osmometer method for predicting leaf osmotic potential at full turgor (πo), a key metric of leaf-level drought tolerance, has resulted in a 50-fold increase in the measurement speed of this trait; however, the applicability of this method has only been tested in woody species and crops. Here, we assess the osmometer method for use in herbaceous grassland species and test whether πo is an appropriate plant trait for understanding drought strategies of herbaceous species as well as species distributions along climate gradients. Our model for predicting leaf turgor loss point (πTLP) from πo (πTLP = 0.80πo-0.845) is nearly identical to the model previously presented for woody species. Additionally, πo was highly correlated with πTLP for graminoid species (πtlp = 0.944πo-0.611; r2 = 0.96), a plant functional group previously flagged for having the potential to cause erroneous measurements when using an osmometer. We report that πo, measured with an osmometer, is well correlated with other traits linked to drought tolerance (namely, leaf dry matter content and leaf vulnerability to hydraulic failure) as well as climate extremes linked to water availability. The validation of the osmometer method in an herb-dominated ecosystem paves the way for rapid community-scale surveys of drought tolerance across plant functional groups, which could improve trait-based predictions of ecosystem responses to climate change.
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Salazar-Tortosa D, Castro J, Villar-Salvador P, Viñegla B, Matías L, Michelsen A, Rubio de Casas R, Querejeta JI. The "isohydric trap": A proposed feedback between water shortage, stomatal regulation, and nutrient acquisition drives differential growth and survival of European pines under climatic dryness. GLOBAL CHANGE BIOLOGY 2018; 24:4069-4083. [PMID: 29768696 DOI: 10.1111/gcb.14311] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/11/2018] [Indexed: 05/15/2023]
Abstract
Climatic dryness imposes limitations on vascular plant growth by reducing stomatal conductance, thereby decreasing CO2 uptake and transpiration. Given that transpiration-driven water flow is required for nutrient uptake, climatic stress-induced nutrient deficit could be a key mechanism for decreased plant performance under prolonged drought. We propose the existence of an "isohydric trap," a dryness-induced detrimental feedback leading to nutrient deficit and stoichiometry imbalance in strict isohydric species. We tested this framework in a common garden experiment with 840 individuals of four ecologically contrasting European pines (Pinus halepensis, P. nigra, P. sylvestris, and P. uncinata) at a site with high temperature and low soil water availability. We measured growth, survival, photochemical efficiency, stem water potentials, leaf isotopic composition (δ13 C, δ18 O), and nutrient concentrations (C, N, P, K, Zn, Cu). After 2 years, the Mediterranean species Pinus halepensis showed lower δ18 O and higher δ13 C values than the other species, indicating higher time-integrated transpiration and water-use efficiency (WUE), along with lower predawn and midday water potentials, higher photochemical efficiency, higher leaf P, and K concentrations, more balanced N:P and N:K ratios, and much greater dry-biomass (up to 63-fold) and survival (100%). Conversely, the more mesic mountain pine species showed higher leaf δ18 O and lower δ13 C, indicating lower transpiration and WUE, higher water potentials, severe P and K deficiencies and N:P and N:K imbalances, and poorer photochemical efficiency, growth, and survival. These results support our hypothesis that vascular plant species with tight stomatal regulation of transpiration can become trapped in a feedback cycle of nutrient deficit and imbalance that exacerbates the detrimental impacts of climatic dryness on performance. This overlooked feedback mechanism may hamper the ability of isohydric species to respond to ongoing global change, by aggravating the interactive impacts of stoichiometric imbalance and water stress caused by anthropogenic N deposition and hotter droughts, respectively.
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Affiliation(s)
- Diego Salazar-Tortosa
- Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Jorge Castro
- Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Pedro Villar-Salvador
- Forest Ecology and Restoration Group, Departamento de Ciencias de la Vida, Universidad de Alcalá, Madrid, Spain
| | - Benjamín Viñegla
- Departamento de Biología Animal, Biología Vegetal y Ecología, Facultad de Ciencias Experimentales, Universidad de Jaén, Jaén, Spain
| | - Luis Matías
- Departamento de Biología Animal, Biología Vegetal y Ecología, Facultad de Ciencias Experimentales, Universidad de Jaén, Jaén, Spain
| | - Anders Michelsen
- Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Copenhagen Ø, Denmark
| | - Rafael Rubio de Casas
- Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - José I Querejeta
- Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Murcia, Spain
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Liu YY, Wang AY, An YN, Lian PY, Wu DD, Zhu JJ, Meinzer FC, Hao GY. Hydraulics play an important role in causing low growth rate and dieback of aging Pinus sylvestris var. mongolica trees in plantations of Northeast China. PLANT, CELL & ENVIRONMENT 2018; 41:1500-1511. [PMID: 29424933 DOI: 10.1111/pce.13160] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 01/25/2018] [Accepted: 01/25/2018] [Indexed: 05/08/2023]
Abstract
The frequently observed forest decline in water-limited regions may be associated with impaired tree hydraulics, but the precise physiological mechanisms remain poorly understood. We compared hydraulic architecture of Mongolian pine (Pinus sylvestris var. mongolica) trees of different size classes from a plantation and a natural forest site to test whether greater hydraulic limitation with increasing size plays an important role in tree decline observed in the more water-limited plantation site. We found that trees from plantations overall showed significantly lower stem hydraulic efficiency. More importantly, plantation-grown trees showed significant declines in stem hydraulic conductivity and hydraulic safety margins as well as syndromes of stronger drought stress with increasing size, whereas no such trends were observed at the natural forest site. Most notably, the leaf to sapwood area ratio (LA/SA) showed a strong linear decline with increasing tree size at the plantation site. Although compensatory adjustments in LA/SA may mitigate the effect of increased water stress in larger trees, they may result in greater risk of carbon imbalance, eventually limiting tree growth at the plantation site. Our results provide a potential mechanistic explanation for the widespread decline of Mongolian pine trees in plantations of Northern China.
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Affiliation(s)
- Yan-Yan Liu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Guangxi Teachers Education University, No. 175 Mingxiu East Road, Nanning, 530001, China
| | - Ai-Ying Wang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu-Ning An
- Institute of Sand Fixation and Silviculture, Liaoning Province, Fuxin, 123000, China
| | - Pei-Yong Lian
- Daxinganling Academy of Forest Science of Inner Mongolia, Yakeshi, 022150, China
| | - De-Dong Wu
- Institute of Sand Fixation and Silviculture, Liaoning Province, Fuxin, 123000, China
| | - Jiao-Jun Zhu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
| | - Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR, 97331, USA
| | - Guang-You Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
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Hahm WJ, Dietrich WE, Dawson TE. Controls on the distribution and resilience of
Quercus garryana
: ecophysiological evidence of oak's water‐limitation tolerance. Ecosphere 2018. [DOI: 10.1002/ecs2.2218] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Affiliation(s)
- W. Jesse Hahm
- Department of Earth and Planetary Science University of California – Berkeley Berkeley California 94720 USA
| | - William E. Dietrich
- Department of Earth and Planetary Science University of California – Berkeley Berkeley California 94720 USA
| | - Todd E. Dawson
- Center for Stable Isotope Biogeochemistry Department of Integrative Biology University of California – Berkeley Berkeley California 94720 USA
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42
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Cernusak LA, Ubierna N, Jenkins MW, Garrity SR, Rahn T, Powers HH, Hanson DT, Sevanto S, Wong SC, McDowell NG, Farquhar GD. Unsaturation of vapour pressure inside leaves of two conifer species. Sci Rep 2018; 8:7667. [PMID: 29769592 PMCID: PMC5955884 DOI: 10.1038/s41598-018-25838-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/30/2018] [Indexed: 11/09/2022] Open
Abstract
Stomatal conductance (gs) impacts both photosynthesis and transpiration, and is therefore fundamental to the global carbon and water cycles, food production, and ecosystem services. Mathematical models provide the primary means of analysing this important leaf gas exchange parameter. A nearly universal assumption in such models is that the vapour pressure inside leaves (ei) remains saturated under all conditions. The validity of this assumption has not been well tested, because so far ei cannot be measured directly. Here, we test this assumption using a novel technique, based on coupled measurements of leaf gas exchange and the stable isotope compositions of CO2 and water vapour passing over the leaf. We applied this technique to mature individuals of two semiarid conifer species. In both species, ei routinely dropped below saturation when leaves were exposed to moderate to high air vapour pressure deficits. Typical values of relative humidity in the intercellular air spaces were as low 0.9 in Juniperus monosperma and 0.8 in Pinus edulis. These departures of ei from saturation caused significant biases in calculations of gs and the intercellular CO2 concentration. Our results refute the longstanding assumption of saturated vapour pressure in plant leaves under all conditions.
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Affiliation(s)
- Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Queensland, Australia.
| | - Nerea Ubierna
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Michael W Jenkins
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, California, USA
| | | | - Thom Rahn
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Heath H Powers
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - David T Hanson
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Suan Chin Wong
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Nate G McDowell
- Earth Systems Analysis and Modelling Group, Pacific Northwest National Laboratory Richland, Washington, USA
| | - Graham D Farquhar
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
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43
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Zlobin IE, Ivanov YV, Kartashov AV, Kuznetsov VV. Impact of drought stress induced by polyethylene glycol on growth, water relations and cell viability of Norway spruce seedlings. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:8951-8962. [PMID: 29332275 DOI: 10.1007/s11356-017-1131-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 12/26/2017] [Indexed: 06/07/2023]
Abstract
We investigated physiological responses of 7-week-old Norway spruce seedlings to water deficits of different intensities. Hydroponically grown seedlings were subjected to mild (-0.15 MPa), strong (-0.5 and -1.0 MPa) and extreme (-1.5 MPa) water deficit induced by polyethylene glycol 6000, and their growth parameters, water status and physiological activity were analyzed. Seedlings effectively restricted water loss under drought, and even under extreme water deficit, shoot relative water content did not fall below 85%. Water stress induced substantial decreases in the osmotic potentials of root and needle cell sap, up to 0.3-0.4 MPa under extreme water deficit, though this did not result from water loss or accumulation of K+ and Na+ ions. Seedling growth was very susceptible to water stress because of poor capacity for cell wall adjustment. Water stress injured seedling roots, as evidenced by the loss of root cell physiological activity estimated by the ability to hydrolyse fluorescein diacetate and by increased root calcium content up to 8-10-fold under extreme water stress. At the same time, root hair growth was enhanced, especially under mild water deficit, which increased the root water-absorbing capacity. In summary, seedlings of Norway spruce were characterized by high susceptibility to water stress and concurrently by pronounced ability to maintain water status. These characteristics are fully consistent with spruce confinement to moist habitats.
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Affiliation(s)
- Ilya E Zlobin
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
| | - Yury V Ivanov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia.
- , Moscow, Russia.
| | - Alexander V Kartashov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
| | - Vladimir V Kuznetsov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
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44
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Johnson DM, Berry ZC, Baker KV, Smith DD, McCulloh KA, Domec J. Leaf hydraulic parameters are more plastic in species that experience a wider range of leaf water potentials. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13049] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Z. Carter Berry
- Department of Natural Resources and the Environment University of New Hampshire Durham NH USA
| | | | - Duncan D. Smith
- Department of Botany University of Wisconsin‐Madison Madison WI USA
| | | | - Jean‐Christophe Domec
- Bordeaux Sciences Agro UMR INRA‐ISPA 1391 Gradignan France
- Nicholas School of the Environment Duke University Durham NC USA
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45
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Nolan RH, Tarin T, Santini NS, McAdam SAM, Ruman R, Eamus D. Differences in osmotic adjustment, foliar abscisic acid dynamics, and stomatal regulation between an isohydric and anisohydric woody angiosperm during drought. PLANT, CELL & ENVIRONMENT 2017; 40:3122-3134. [PMID: 28982212 DOI: 10.1111/pce.13077] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 09/18/2017] [Accepted: 09/20/2017] [Indexed: 06/07/2023]
Abstract
Species are often classified along a continuum from isohydric to anisohydric, with isohydric species exhibiting tighter regulation of leaf water potential through stomatal closure in response to drought. We investigated plasticity in stomatal regulation in an isohydric (Eucalyptus camaldulensis) and an anisohydric (Acacia aptaneura) angiosperm species subject to repeated drying cycles. We also assessed foliar abscisic acid (ABA) content dynamics, aboveground/belowground biomass allocation and nonstructural carbohydrates. The anisohydric species exhibited large plasticity in the turgor loss point (ΨTLP ), with plants subject to repeated drying exhibiting lower ΨTLP and correspondingly larger stomatal conductance at low water potential, compared to plants not previously exposed to drought. The anisohydric species exhibited a switch from ABA to water potential-driven stomatal closure during drought, a response previously only reported for anisohydric gymnosperms. The isohydric species showed little osmotic adjustment, with no evidence of switching to water potential-driven stomatal closure, but did exhibit increased root:shoot ratios. There were no differences in carbohydrate depletion between species. We conclude that a large range in ΨTLP and biphasic ABA dynamics are indicative of anisohydric species, and these traits are associated with exposure to low minimum foliar water potential, dense sapwood and large resistance to xylem embolism.
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Affiliation(s)
- Rachael H Nolan
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, Ultimo, New South Wales, 2007, Australia
| | - Tonantzin Tarin
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, Ultimo, New South Wales, 2007, Australia
| | - Nadia S Santini
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, Ultimo, New South Wales, 2007, Australia
- Institute of Ecology, National Autonomous University of Mexico, External Circuit S/N annex Botanical Garden exterior, University City, Mexico City, 04500, Mexico
| | - Scott A M McAdam
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, 7001, Australia
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Rizwana Ruman
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, Ultimo, New South Wales, 2007, Australia
| | - Derek Eamus
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, Ultimo, New South Wales, 2007, Australia
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46
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Nolan RH, Fairweather KA, Tarin T, Santini NS, Cleverly J, Faux R, Eamus D. Divergence in plant water-use strategies in semiarid woody species. FUNCTIONAL PLANT BIOLOGY : FPB 2017; 44:1134-1146. [PMID: 32480639 DOI: 10.1071/fp17079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/16/2017] [Indexed: 06/11/2023]
Abstract
Partitioning of water resources amongst plant species within a single climate envelope is possible if the species differ in key hydraulic traits. We examined 11 bivariate trait relationships across nine woody species found in the Ti-Tree basin of central Australia. We found that species with limited access to soil moisture, evidenced by low pre-dawn leaf water potential, displayed anisohydric behaviour (e.g. large seasonal fluctuations in minimum leaf water potential), had greater sapwood density and lower osmotic potential at full turgor. Osmotic potential at full turgor was positively correlated with the leaf water potential at turgor loss, which was, in turn, positively correlated with the water potential at incipient stomatal closure. We also observed divergent behaviour in two species of Mulga, a complex of closely related Acacia species which range from tall shrubs to low trees and dominate large areas of arid and semiarid Australia. These Mulga species had much lower minimum leaf water potentials and lower specific leaf area compared with the other seven species. Finally, one species, Hakea macrocarpa A.Cunn ex.R.Br., had traits that may allow it to tolerate seasonal dryness (through possession of small specific leaf area and cavitation resistant xylem) despite exhibiting cellular water relations that were similar to groundwater-dependent species. We conclude that traits related to water transport and leaf water status differ across species that experience differences in soil water availability and that this enables a diversity of species to exist in this low rainfall environment.
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Affiliation(s)
- Rachael H Nolan
- Terrestrial Ecohydrology Research Group, School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Kendal A Fairweather
- Terrestrial Ecohydrology Research Group, School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Tonantzin Tarin
- Terrestrial Ecohydrology Research Group, School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Nadia S Santini
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - James Cleverly
- Terrestrial Ecohydrology Research Group, School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Ralph Faux
- Terrestrial Ecohydrology Research Group, School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Derek Eamus
- Terrestrial Ecohydrology Research Group, School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
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47
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Grossiord C, Sevanto S, Borrego I, Chan AM, Collins AD, Dickman LT, Hudson PJ, McBranch N, Michaletz ST, Pockman WT, Ryan M, Vilagrosa A, McDowell NG. Tree water dynamics in a drying and warming world. PLANT, CELL & ENVIRONMENT 2017; 40:1861-1873. [PMID: 28556263 DOI: 10.1111/pce.12991] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 05/02/2017] [Accepted: 05/09/2017] [Indexed: 05/16/2023]
Abstract
Disentangling the relative impacts of precipitation reduction and vapour pressure deficit (VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density (FD ), stomatal conductance (Gs ), hydraulic conductivity (KL ) and xylem anatomy in piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced the sensibility of stomata to VPD for both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD , Gs and KL . Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs , FD and KL took place to similar levels as under single stresses for both species. Our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions.
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Affiliation(s)
- Charlotte Grossiord
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Isaac Borrego
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Allison M Chan
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Adam D Collins
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Lee T Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Patrick J Hudson
- Department of Biology, MSC03 202, University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - Natalie McBranch
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Sean T Michaletz
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - William T Pockman
- Department of Biology, MSC03 202, University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - Max Ryan
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Alberto Vilagrosa
- Fundación CEAM, Joint Research Unit University of Alicante - CEAM, Univ. Alicante, PO Box 99, 03080, Alicante, Spain
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
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48
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Plant Water Status Indicators for Irrigation Scheduling Associated with Iso- and Anisohydric Behavior: Vine and Plum Trees. HORTICULTURAE 2017. [DOI: 10.3390/horticulturae3030047] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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49
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Farrell C, Szota C, Arndt SK. Does the turgor loss point characterize drought response in dryland plants? PLANT, CELL & ENVIRONMENT 2017; 40:1500-1511. [PMID: 28342210 DOI: 10.1111/pce.12948] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 02/22/2017] [Accepted: 02/24/2017] [Indexed: 05/18/2023]
Abstract
The water potential at turgor loss point (Ψtlp ) has been suggested as a key functional trait for determining plant drought tolerance, because of its close relationship with stomatal closure. Ψtlp may indicate drought tolerance as plants, which maintain gas exchange at lower midday water potentials as soil water availability declines also have lower Ψtlp . We evaluated 17 species from seasonally dry habitats, representing a range of life-forms, under well-watered and drought conditions, to determine how Ψtlp relates to stomatal sensitivity (pre-dawn water potential at stomatal closure: Ψgs0 ) and drought strategy (degree of isohydry or anisohydry; ΔΨMD between well-watered conditions and stomatal closure). Although Ψgs0 was related to Ψtlp , Ψgs0 was better related to drought strategy (ΔΨMD ). Drought avoiders (isohydric) closed stomata at water potentials higher than their Ψtlp ; whereas, drought tolerant (anisohydric) species maintained stomatal conductance at lower water potentials than their Ψtlp and were more dehydration tolerant. There was no significant relationship between Ψtlp and ΔΨMD . While Ψtlp has been related to biome water availability, we found that Ψtlp did not relate strongly to stomatal closure or drought strategy, for either drought avoiders or tolerators. We therefore suggest caution in using Ψtlp to predict vulnerability to drought.
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Affiliation(s)
- Claire Farrell
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, 3121, Australia
| | - Christopher Szota
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, 3121, Australia
| | - Stefan K Arndt
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria, 3121, Australia
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50
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Martínez-Vilalta J, Garcia-Forner N. Water potential regulation, stomatal behaviour and hydraulic transport under drought: deconstructing the iso/anisohydric concept. PLANT, CELL & ENVIRONMENT 2017; 40:962-976. [PMID: 27739594 DOI: 10.1111/pce.12846] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 05/02/2023]
Abstract
In this review, we address the relationship between stomatal behaviour, water potential regulation and hydraulic transport in plants, focusing on the implications for the iso/anisohydric classification of plant drought responses at seasonal timescales. We first revise the history of the isohydric concept and its possible definitions. Then, we use published data to answer two main questions: (1) is greater stomatal control in response to decreasing water availability associated with a tighter regulation of leaf water potential (ΨL ) across species? and (2) is there an association between tighter ΨL regulation (~isohydric behaviour) and lower leaf conductance over time during a drought event? These two questions are addressed at two levels: across species growing in different sites and comparing only species coexisting at a given site. Our analyses show that, across species, a tight regulation of ΨL is not necessarily associated with greater stomatal control or with more constrained assimilation during drought. Therefore, iso/anisohydry defined in terms of ΨL regulation cannot be used as an indicator of a specific mechanism of drought-induced mortality or as a proxy for overall plant vulnerability to drought.
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Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, Barcelona, E-08193, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, E-08193, Spain
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