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Jardine KJ, Som S, Gallo LB, Demus J, Domingues TF, Wistrom CM, Gu L, Tcherkez G, Niinemets Ü. Concurrent Measurement of O 2 Production and Isoprene Emission During Photosynthesis: Pros, Cons and Metabolic Implications of Responses to Light, CO 2 and Temperature. PLANT, CELL & ENVIRONMENT 2024. [PMID: 39248643 DOI: 10.1111/pce.15124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 08/13/2024] [Accepted: 08/17/2024] [Indexed: 09/10/2024]
Abstract
Traditional leaf gas exchange experiments have focused on net CO2 exchange (Anet). Here, using California poplar (Populus trichocarpa), we coupled measurements of net oxygen production (NOP), isoprene emissions and δ18O in O2 to traditional CO2/H2O gas exchange with chlorophyll fluorescence, and measured light, CO2 and temperature response curves. This allowed us to obtain a comprehensive picture of the photosynthetic redox budget including electron transport rate (ETR) and estimates of the mean assimilatory quotient (AQ = Anet/NOP). We found that Anet and NOP were linearly correlated across environmental gradients with similar observed AQ values during light (1.25 ± 0.05) and CO2 responses (1.23 ± 0.07). In contrast, AQ was suppressed during leaf temperature responses in the light (0.87 ± 0.28), potentially due to the acceleration of alternative ETR sinks like lipid synthesis. Anet and NOP had an optimum temperature (Topt) of 31°C, while ETR and δ18O in O2 (35°C) and isoprene emissions (39°C) had distinctly higher Topt. The results confirm a tight connection between water oxidation and ETR and support a view of light-dependent lipid synthesis primarily driven by photosynthetic ATP/NADPH not consumed by the Calvin-Benson cycle, as an important thermotolerance mechanism linked with high rates of (photo)respiration and CO2/O2 recycling.
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Affiliation(s)
- Kolby Jeremiah Jardine
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, California, USA
| | - Suman Som
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, California, USA
| | - Luiza Beraldi Gallo
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, California, USA
- FFCLRP, Departamento de Biologia, Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Jilian Demus
- College of Natural Resources, University of California, Berkeley, Berkeley, California, USA
| | | | | | - Lianhong Gu
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, Tennessee, USA
| | - Guillaume Tcherkez
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- Institut de Recherche en Horticulture et Semences, INRAE, Université d'Angers, Beaucouzé, France
| | - Ülo Niinemets
- Chair of Plant Biology and Crop Science, Estonian University of Life Sciences, Tartu, Estonia
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Wright CL, West JB, de Lima ALA, Souza ES, Medeiros M, Wilcox BP. Contrasting water-use strategies revealed by species-specific transpiration dynamics in the Caatinga dry forest. TREE PHYSIOLOGY 2024; 44:tpad137. [PMID: 37935389 DOI: 10.1093/treephys/tpad137] [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: 07/04/2023] [Accepted: 11/01/2023] [Indexed: 11/09/2023]
Abstract
In forest ecosystems, transpiration (T) patterns are important for quantifying water and carbon fluxes and are major factors in predicting ecosystem change. Seasonal changes in rainfall and soil water content can alter the sensitivity of sap flux density to daily variations in vapor pressure deficit (VPD). This sensitivity is species-specific and is thought to be related to hydraulic strategies. The aim of this work is to better understand how the sap flux density of species with low versus high wood density differ in their sensitivity to VPD and soil water content and how potentially opposing water-use strategies influence T dynamics, and ultimately, correlations to evapotranspiration (ET). We use hysteresis area analysis to quantify the sensitivity of species-specific sap flux density to changes in the VPD, breakpoint-based models to determine the soil water content threshold instigating a T response and multiscalar wavelet coherency to correlate T to ET. We found that low wood density Commiphora leptophloeos (Mart.) Gillett had a more dynamic T pattern, a greater sensitivity to VPD at high soil water content, required a higher soil water content threshold for this sensitivity to be apparent, and had a significant coherency correlation with ET at daily to monthly timescales. This behavior is consistent with a drought avoidance strategy. High wood density Cenostigma pyramidale (Tul.) E. Gagnon & G. P. Lewis, conversely, had a more stable T pattern, responded to VPD across a range of soil water content, tolerated a lower soil water content threshold to T, and had a significant coherency correlation with ET at weekly timescales. This behavior is consistent with a drought-tolerant strategy. We build on previous research to show that these species have contrasting water-use strategies that should be considered in large-scale modeling efforts.
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Affiliation(s)
- Cynthia L Wright
- Southern Research Station, USDA Forest Service, 4700 Old Kingston Pike, Knoxville, TN 37919, USA
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama City, Panama
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37830, USA
- Ecology and Conservation Biology, Texas A&M University, 534 John Kimbrough Blvd, College Station, TX 77843, USA
| | - Jason B West
- Ecology and Conservation Biology, Texas A&M University, 534 John Kimbrough Blvd, College Station, TX 77843, USA
| | - André L A de Lima
- Universidade Federal Rural de Pernambuco, Unidade Acadêmica de Serra Talhada, Av. Gregório Ferraz Nogueira, S/n, Bairro: José Tomé de Souza Ramos, Caixa Postal 063, CEP: 56.909-535, Serra Talhada, Pernambuco, Brazil
| | - Eduardo S Souza
- Universidade Federal Rural de Pernambuco, Unidade Acadêmica de Serra Talhada, Av. Gregório Ferraz Nogueira, S/n, Bairro: José Tomé de Souza Ramos, Caixa Postal 063, CEP: 56.909-535, Serra Talhada, Pernambuco, Brazil
| | - Maria Medeiros
- Universidade Federal Rural de Pernambuco, Unidade Acadêmica de Serra Talhada, Av. Gregório Ferraz Nogueira, S/n, Bairro: José Tomé de Souza Ramos, Caixa Postal 063, CEP: 56.909-535, Serra Talhada, Pernambuco, Brazil
- Federal University of Pernambuco, Department of Botany, Avenida Professor Moraes Rego, s/n, Cidade Universitária, CEP: 50670-901, Recife, Pernambuco, Brazil
| | - Bradford P Wilcox
- Ecology and Conservation Biology, Texas A&M University, 534 John Kimbrough Blvd, College Station, TX 77843, USA
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Lamour J, Souza DC, Gimenez BO, Higuchi N, Chave J, Chambers J, Rogers A. Wood-density has no effect on stomatal control of leaf-level water use efficiency in an Amazonian forest. PLANT, CELL & ENVIRONMENT 2023; 46:3806-3821. [PMID: 37635450 DOI: 10.1111/pce.14704] [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: 03/24/2023] [Revised: 07/20/2023] [Accepted: 08/16/2023] [Indexed: 08/29/2023]
Abstract
Forest disturbances increase the proportion of fast-growing tree species compared to slow-growing ones. To understand their relative capacity for carbon uptake and their vulnerability to climate change, and to represent those differences in Earth system models, it is necessary to characterise the physiological differences in their leaf-level control of water use efficiency and carbon assimilation. We used wood density as a proxy for the fast-slow growth spectrum and tested the assumption that trees with a low wood density (LWD) have a lower water-use efficiency than trees with a high wood density (HWD). We selected 5 LWD tree species and 5 HWD tree species growing in the same location in an Amazonian tropical forest and measured in situ steady-state gas exchange on top-of-canopy leaves with parallel sampling and measurement of leaf mass area and leaf nitrogen content. We found that LWD species invested more nitrogen in photosynthetic capacity than HWD species, had higher photosynthetic rates and higher stomatal conductance. However, contrary to expectations, we showed that the stomatal control of the balance between transpiration and carbon assimilation was similar in LWD and HWD species and that they had the same dark respiration rates.
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Affiliation(s)
- Julien Lamour
- Department of Environmental & Climate Sciences, Brookhaven National Laboratory, Upton, New York, USA
- Evolution and Biological Diversity (EDB), CNRS/IRD/UPS, Toulouse, France
| | - Daisy C Souza
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
| | - Bruno O Gimenez
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
- Department of Geography, University of California, Berkeley, California, USA
| | - Niro Higuchi
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
| | - Jérôme Chave
- Evolution and Biological Diversity (EDB), CNRS/IRD/UPS, Toulouse, France
| | - Jeffrey Chambers
- Department of Geography, University of California, Berkeley, California, USA
| | - Alistair Rogers
- Department of Environmental & Climate Sciences, Brookhaven National Laboratory, Upton, New York, USA
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Brum M, Vadeboncoeur M, Asbjornsen H, Puma Vilca BL, Galiano D, Horwath AB, Metcalfe DB. Ecophysiological controls on water use of tropical cloud forest trees in response to experimental drought. TREE PHYSIOLOGY 2023; 43:1514-1532. [PMID: 37209136 DOI: 10.1093/treephys/tpad070] [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: 02/18/2023] [Revised: 05/03/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023]
Abstract
Tropical montane cloud forests (TMCFs) are expected to experience more frequent and prolonged droughts over the coming century, yet understanding of TCMF tree responses to moisture stress remains weak compared with the lowland tropics. We simulated a severe drought in a throughfall reduction experiment (TFR) for 2 years in a Peruvian TCMF and evaluated the physiological responses of several dominant species (Clusia flaviflora Engl., Weinmannia bangii (Rusby) Engl., Weinmannia crassifolia Ruiz & Pav. and Prunus integrifolia (C. Presl) Walp). Measurements were taken of (i) sap flow; (ii) diurnal cycles of stem shrinkage, stem moisture variation and water-use; and (iii) intrinsic water-use efficiency (iWUE) estimated from foliar δ13C. In W. bangii, we used dendrometers and volumetric water content (VWC) sensors to quantify daily cycles of stem water storage. In 2 years of sap flow (Js) data, we found a threshold response of water use to vapor pressure deficit vapor pressure deficit (VPD) > 1.07 kPa independent of treatment, though control trees used more soil water than the treatment trees. The daily decline in water use in the TFR trees was associated with a strong reduction in both morning and afternoon Js rates at a given VPD. Soil moisture also affected the hysteresis strength between Js and VPD. Reduced hysteresis under moisture stress implies that TMCFs are strongly dependent on shallow soil water. Additionally, we suggest that hysteresis can serve as a sensitive indicator of environmental constraints on plant function. Finally, 6 months into the experiment, the TFR treatment significantly increased iWUE in all study species. Our results highlight the conservative behavior of TMCF tree water use under severe soil drought and elucidate physiological thresholds related to VPD and its interaction with soil moisture. The observed strongly isohydric response likely incurs a cost to the carbon balance of the tree and reduces overall ecosystem carbon uptake.
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Affiliation(s)
- Mauro Brum
- Department of Natural Resources & the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
| | - Matthew Vadeboncoeur
- Earth Systems Research Center, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA
| | - Heidi Asbjornsen
- Department of Natural Resources & the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
- Earth Systems Research Center, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA
| | - Beisit L Puma Vilca
- Facultad de Ciencias Biológicas, Universidad Nacional de San Antonio Abad del Cusco, Av. de La Cultura 773, Cusco, Cusco Province 08000, Peru
- Asociación Civil Sin Fines De Lucro Para La Biodiversidad, Investigación Y Desarrollo Ambiental En Ecosistemas Tropicales (ABIDA), Urbanización Ucchullo Grande, Avenida Argentina F-9, Cusco, Perú
| | - Darcy Galiano
- Facultad de Ciencias Biológicas, Universidad Nacional de San Antonio Abad del Cusco, Av. de La Cultura 773, Cusco, Cusco Province 08000, Peru
- Asociación Civil Sin Fines De Lucro Para La Biodiversidad, Investigación Y Desarrollo Ambiental En Ecosistemas Tropicales (ABIDA), Urbanización Ucchullo Grande, Avenida Argentina F-9, Cusco, Perú
| | - Aline B Horwath
- Asociación Civil Sin Fines De Lucro Para La Biodiversidad, Investigación Y Desarrollo Ambiental En Ecosistemas Tropicales (ABIDA), Urbanización Ucchullo Grande, Avenida Argentina F-9, Cusco, Perú
| | - Daniel B Metcalfe
- Department of Ecology & Environmental Science, Umeå University, KBC-huset, Linnaeus väg 6, Umeå 901 87, Sweden
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No evidence of canopy-scale leaf thermoregulation to cool leaves below air temperature across a range of forest ecosystems. Proc Natl Acad Sci U S A 2022; 119:e2205682119. [PMID: 36095211 PMCID: PMC9499539 DOI: 10.1073/pnas.2205682119] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding and predicting the relationship between leaf temperature (Tleaf) and air temperature (Tair) is essential for projecting responses to a warming climate, as studies suggest that many forests are near thermal thresholds for carbon uptake. Based on leaf measurements, the limited leaf homeothermy hypothesis argues that daytime Tleaf is maintained near photosynthetic temperature optima and below damaging temperature thresholds. Specifically, leaves should cool below Tair at higher temperatures (i.e., > ∼25-30°C) leading to slopes <1 in Tleaf/Tair relationships and substantial carbon uptake when leaves are cooler than air. This hypothesis implies that climate warming will be mitigated by a compensatory leaf cooling response. A key uncertainty is understanding whether such thermoregulatory behavior occurs in natural forest canopies. We present an unprecedented set of growing season canopy-level leaf temperature (Tcan) data measured with thermal imaging at multiple well-instrumented forest sites in North and Central America. Our data do not support the limited homeothermy hypothesis: canopy leaves are warmer than air during most of the day and only cool below air in mid to late afternoon, leading to Tcan/Tair slopes >1 and hysteretic behavior. We find that the majority of ecosystem photosynthesis occurs when canopy leaves are warmer than air. Using energy balance and physiological modeling, we show that key leaf traits influence leaf-air coupling and ultimately the Tcan/Tair relationship. Canopy structure also plays an important role in Tcan dynamics. Future climate warming is likely to lead to even greater Tcan, with attendant impacts on forest carbon cycling and mortality risk.
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Spanner GC, Gimenez BO, Wright CL, Menezes VS, Newman BD, Collins AD, Jardine KJ, Negrón-Juárez RI, Lima AJN, Rodrigues JR, Chambers JQ, Higuchi N, Warren JM. Dry Season Transpiration and Soil Water Dynamics in the Central Amazon. FRONTIERS IN PLANT SCIENCE 2022; 13:825097. [PMID: 35401584 PMCID: PMC8987125 DOI: 10.3389/fpls.2022.825097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
With current observations and future projections of more intense and frequent droughts in the tropics, understanding the impact that extensive dry periods may have on tree and ecosystem-level transpiration and concurrent carbon uptake has become increasingly important. Here, we investigate paired soil and tree water extraction dynamics in an old-growth upland forest in central Amazonia during the 2018 dry season. Tree water use was assessed via radial patterns of sap flow in eight dominant canopy trees, each a different species with a range in diameter, height, and wood density. Paired multi-sensor soil moisture probes used to quantify volumetric water content dynamics and soil water extraction within the upper 100 cm were installed adjacent to six of those trees. To link depth-specific water extraction patterns to root distribution, fine root biomass was assessed through the soil profile to 235 cm. To scale tree water use to the plot level (stand transpiration), basal area was measured for all trees within a 5 m radius around each soil moisture probe. The sensitivity of tree transpiration to reduced precipitation varied by tree, with some increasing and some decreasing in water use during the dry period. Tree-level water use scaled with sapwood area, from 11 to 190 L per day. Stand level water use, based on multiple plots encompassing sap flow and adjacent trees, varied from ∼1.7 to 3.3 mm per day, increasing linearly with plot basal area. Soil water extraction was dependent on root biomass, which was dense at the surface (i.e., 45% in the upper 5 cm) and declined dramatically with depth. As the dry season progressed and the upper soil dried, soil water extraction shifted to deeper levels and model projections suggest that much of the water used during the month-long dry-down could be extracted from the upper 2-3 m. Results indicate variation in rates of soil water extraction across the research area and, temporally, through the soil profile. These results provide key information on whole-tree contributions to transpiration by canopy trees as water availability changes. In addition, information on simultaneous stand level dynamics of soil water extraction that can inform mechanistic models that project tropical forest response to drought.
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Affiliation(s)
| | - Bruno O. Gimenez
- National Institute of Amazonian Research (INPA), Manaus, Brazil
- Smithsonian Tropical Research Institute (STRI), Panama City, Panama
| | - Cynthia L. Wright
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, TN, United States
| | | | - Brent D. Newman
- Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Adam D. Collins
- Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Kolby J. Jardine
- National Institute of Amazonian Research (INPA), Manaus, Brazil
- Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | | | | | | | - Jeffrey Q. Chambers
- National Institute of Amazonian Research (INPA), Manaus, Brazil
- Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Geography, University of California, Berkeley, Berkeley, CA, United States
| | - Niro Higuchi
- National Institute of Amazonian Research (INPA), Manaus, Brazil
| | - Jeffrey M. Warren
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, TN, United States
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7
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Still CJ, Rastogi B, Page GFM, Griffith DM, Sibley A, Schulze M, Hawkins L, Pau S, Detto M, Helliker BR. Imaging canopy temperature: shedding (thermal) light on ecosystem processes. THE NEW PHYTOLOGIST 2021; 230:1746-1753. [PMID: 33666251 DOI: 10.1111/nph.17321] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Canopy temperature Tcan is a key driver of plant function that emerges as a result of interacting biotic and abiotic processes and properties. However, understanding controls on Tcan and forecasting canopy responses to weather extremes and climate change are difficult due to sparse measurements of Tcan at appropriate spatial and temporal scales. Burgeoning observations of Tcan from thermal cameras enable evaluation of energy budget theory and better understanding of how environmental controls, leaf traits and canopy structure influence temperature patterns. The canopy scale is relevant for connecting to remote sensing and testing biosphere model predictions. We anticipate that future breakthroughs in understanding of ecosystem responses to climate change will result from multiscale observations of Tcan across a range of ecosystems.
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Affiliation(s)
- Christopher J Still
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Bharat Rastogi
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, 80309, USA
- Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, 80305, USA
| | - Gerald F M Page
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Dan M Griffith
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Adam Sibley
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Mark Schulze
- H.J. Andrews Experimental Forest, Oregon State University, Blue River, OR, 97413, USA
| | - Linnia Hawkins
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Stephanie Pau
- Department of Geography, Florida State University, Tallahassee, FL, 32304, USA
| | - Matteo Detto
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08540, USA
- Smithsonian Tropical Research Institute, Balboa, Panama
| | - Brent R Helliker
- Department of Biology, University of Pennsylvania, 433 S. University Avenue, Philadelphia, PA, 19104, USA
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