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Asao S, Way DA, Turnbull MH, Stitt M, McDowell NG, Reich PB, Bloomfield KJ, Zaragoza-Castells J, Creek D, O'Sullivan O, Crous KY, Egerton JJG, Mirotchnick N, Weerasinghe LK, Griffin KL, Hurry V, Meir P, Sitch S, Atkin OK. Leaf nonstructural carbohydrate residence time, not concentration, correlates with leaf functional traits following the leaf economic spectrum in woody plants. THE NEW PHYTOLOGIST 2025; 246:1505-1519. [PMID: 39648408 DOI: 10.1111/nph.20315] [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: 07/14/2024] [Accepted: 11/10/2024] [Indexed: 12/10/2024]
Abstract
Nonstructural carbohydrate (NSC) concentrations might reflect the strategies described in the leaf economic spectrum (LES) due to their dependence on photosynthesis and respiration. We examined if NSC concentrations correlate with leaf structure, chemistry, and physiology traits for 114 species from 19 sites and 5 biomes around the globe. Total leaf NSC concentrations varied greatly from 16 to 199 mg g-1 dry mass and were mostly independent of leaf gas exchange and the LES traits. By contrast, leaf NSC residence time was shorter in species with higher rates of photosynthesis, following the fast-slow strategies in the LES. An average leaf held an amount of NSCs that could sustain one night of leaf respiration and could be replenished in just a few hours of photosynthesis under saturating light, indicating that most daily carbon gain is exported. Our results suggest that NSC export is clearly linked to the economics of return on resource investment.
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Affiliation(s)
- Shinichi Asao
- Division of Plant Sciences, Research School of Biology, ARC Centre for Excellence in Plant Energy Biology, The Australian National University, Canberra, 2601, ACT, Australia
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
| | - Danielle A Way
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
- Department of Biology, The University of Western Ontario, London, N6A 5B7, ON, Canada
- Nicholas School of the Environment, Duke University, Durham, 27708, NC, USA
- Terrestrial Ecosystem Science and Technology, Brookhaven National Laboratory, Building 490A, P.O. Box 5000, Upton, 11973-5000, NY, USA
| | - Matthew H Turnbull
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - Mark Stitt
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Wissenschaftspark Potsdam-Golm, Am Mühlenberg 1, Potsdam, 14476, Germany
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Lab, PO Box 999, Richland, 99352, WA, USA
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, 99164-4236, WA, USA
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue North, St Paul, 55108, MN, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, 2751, NSW, Australia
- Institute for Global Change Biology, University of Michigan, Ann Arbor, 48130, MI, USA
| | - Keith J Bloomfield
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK
| | - Joana Zaragoza-Castells
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Amory Building, Exeter, EX4 4RJ, UK
| | - Danielle Creek
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, Ås, 1432, Norway
| | - Odhran O'Sullivan
- Division of Plant Sciences, Research School of Biology, ARC Centre for Excellence in Plant Energy Biology, The Australian National University, Canberra, 2601, ACT, Australia
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
| | - Kristine Y Crous
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, 2751, NSW, Australia
| | - John J G Egerton
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Building 116, Canberra, 2601, ACT, Australia
| | - Nicholas Mirotchnick
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, M5S 3B2, ON, Canada
| | - Lasantha K Weerasinghe
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
- Faculty of Agriculture, University of Peradeniya, Peradeniya, 20400, Sri Lanka
| | - Kevin L Griffin
- Department of Earth and Environmental Sciences, Columbia University, Palisades, 10027, NY, USA
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, 10027, NY, USA
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, 10964, NY, USA
| | - Vaughan Hurry
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, SE-901 84, Sweden
| | - Patrick Meir
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
| | - Stephen Sitch
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Amory Building, Exeter, EX4 4RJ, UK
| | - Owen K Atkin
- Division of Plant Sciences, Research School of Biology, ARC Centre for Excellence in Plant Energy Biology, The Australian National University, Canberra, 2601, ACT, Australia
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 46, Canberra, 2601, ACT, Australia
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An J, Huo H, Liu Q, Jiang Y, Luo H, Hao Y. Physiological and molecular mechanisms of nitrogen in alleviating drought stress in Phoebe bournei. Sci Rep 2025; 15:14684. [PMID: 40287505 PMCID: PMC12033254 DOI: 10.1038/s41598-025-99312-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2024] [Accepted: 04/18/2025] [Indexed: 04/29/2025] Open
Abstract
To explore the mechanisms by which nitrogen alleviates drought stress in Phoebe bournei, this study integrated drought treatment with exogenous nitrogen application to assess physiological characteristics and employed transcriptome sequencing to decipher transcriptional responses. The results indicated that nitrogen fertilizer mitigated leaf wilting in P. bournei under drought stress and significantly enhanced leaf dry weight, fresh weight, thickness, and chlorophyll content. Furthermore, nitrogen improved photosynthesis by inhibiting stomatal closure, enhancing light energy absorption, and accelerating electron transport in PSII. 11 photosynthesis-related genes, including PFP, TRY, LQY, FTSH, FRO, CURT, PETF, ATPF, PETA, CRRSP, and MEN and 17 carbohydrate metabolism-associated genes, such as PWD, GBE1, GAPA, PFKA, RFS, ISA, GLGC, PGK, ALDO, GUX, RX9, MIOX, HCT, BAM, MPFP, and ERNI exhibited differential expression in response to nitrogen. Moreover, nitrogen treatment significantly modulated plant hormone metabolism, with 44 upregulated and 14 downregulated differentially expressed genes (DEGs) primarily associated with jasmonic acid (JA) synthesis and signaling. These findings provide new insights into enhancing the drought tolerance of P. bournei in the context of global climate change.
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Affiliation(s)
- Jing An
- Geography and Environmental Science College, Guizhou Normal University, Guiyang, 550025, China
| | - Honghao Huo
- College of Forestry, Guizhou University, Guiyang, 550025, China.
| | - Qiyuan Liu
- China Agricultural University, Beijing, 100083, China
| | - Yunli Jiang
- The Forestry Science Research Institute of Guizhou Province, Guiyang, 550025, China
| | - Hong Luo
- The Forestry Science Research Institute of Guizhou Province, Guiyang, 550025, China
| | - Yupei Hao
- Department of Modern Engineering, Anshun Technical College, Anshun, 561000, China.
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3
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Li L, Li Y, Ding G. Response mechanism of carbon metabolism of Pinus massoniana to gradient high temperature and drought stress. BMC Genomics 2024; 25:166. [PMID: 38347506 PMCID: PMC10860282 DOI: 10.1186/s12864-024-10054-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/25/2024] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND The carbon metabolism pathway is of paramount importance for the growth and development of plants, exerting a pivotal regulatory role in stress responses. The exacerbation of drought impacts on the plant carbon cycle due to global warming necessitates comprehensive investigation into the response mechanisms of Masson Pine (Pinus massoniana Lamb.), an exemplary pioneer drought-tolerant tree, thereby establishing a foundation for predicting future forest ecosystem responses to climate change. RESULTS The seedlings of Masson Pine were utilized as experimental materials in this study, and the transcriptome, metabolome, and photosynthesis were assessed under varying temperatures and drought intensities. The findings demonstrated that the impact of high temperature and drought on the photosynthetic rate and transpiration rate of Masson Pine seedlings was more pronounced compared to individual stressors. The analysis of transcriptome data revealed that the carbon metabolic pathways of Masson Pine seedlings were significantly influenced by high temperature and drought co-stress, with a particular impact on genes involved in starch and sucrose metabolism. The metabolome analysis revealed that only trehalose and Galactose 1-phosphate were specifically associated with the starch and sucrose metabolic pathways. Furthermore, the trehalose metabolic heat map was constructed by integrating metabolome and transcriptome data, revealing a significant increase in trehalose levels across all three comparison groups. Additionally, the PmTPS1, PmTPS5, and PmTPPD genes were identified as key regulatory genes governing trehalose accumulation. CONCLUSIONS The combined effects of high temperature and drought on photosynthetic rate, transpiration rate, transcriptome, and metabolome were more pronounced than those induced by either high temperature or drought alone. Starch and sucrose metabolism emerged as the pivotal carbon metabolic pathways in response to high temperature and drought stress in Masson pine. Trehalose along with PmTPS1, PmTPS5, and PmTPPD genes played crucial roles as metabolites and key regulators within the starch and sucrose metabolism.
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Affiliation(s)
- Liangliang Li
- Forest Resources and Environment Research Center, Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province, College of Forestry, Guizhou University, 550001, Guiyang, China
- Institute of Mountain Resources of Guizhou Province, Guiyang, China, 550001
| | - Yan Li
- Forest Resources and Environment Research Center, Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province, College of Forestry, Guizhou University, 550001, Guiyang, China
| | - Guijie Ding
- Forest Resources and Environment Research Center, Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province, College of Forestry, Guizhou University, 550001, Guiyang, China.
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Ping J, Cui E, Du Y, Wei N, Zhou J, Wang J, Niu S, Luo Y, Xia J. Enhanced causal effect of ecosystem photosynthesis on respiration during heatwaves. SCIENCE ADVANCES 2023; 9:eadi6395. [PMID: 37878695 PMCID: PMC10599625 DOI: 10.1126/sciadv.adi6395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 09/21/2023] [Indexed: 10/27/2023]
Abstract
Because of global warming, Earth's ecosystems have been experiencing more frequent and severe heatwaves. Heatwaves are expected to tip terrestrial carbon sequestration by elevating ecosystem respiration and suppressing gross primary productivity (GPP). Here, using the convergent cross-mapping technique, this study detected positive bidirectional causal effects between GPP and respiration in two unprecedented European heatwaves. Heatwaves enhanced the causal effect strength of GPP on respiration rather than respiration on GPP across 40 site-years of observations. Further analyses and global simulations revealed spatial heterogeneity in the heatwave response of the causal link strength between GPP and respiration, which was jointly driven by the local climate and vegetation properties. However, the causal effect strength of GPP on respiration showed considerable uncertainties in CMIP6 models. This study reveals an enhanced causal link strength between GPP and respiration during heatwaves, shedding light on improving projections for terrestrial carbon sink dynamics under future climate extremes.
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Affiliation(s)
- Jiaye Ping
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, State Key Laboratory of Estuarine and Coastal Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Research Center for Global Change and Complex Ecosystems, Institute of Eco-Chongming, East China Normal University, Shanghai 200241, China
| | - Erqian Cui
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, State Key Laboratory of Estuarine and Coastal Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Research Center for Global Change and Complex Ecosystems, Institute of Eco-Chongming, East China Normal University, Shanghai 200241, China
| | - Ying Du
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, State Key Laboratory of Estuarine and Coastal Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Research Center for Global Change and Complex Ecosystems, Institute of Eco-Chongming, East China Normal University, Shanghai 200241, China
| | - Ning Wei
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, State Key Laboratory of Estuarine and Coastal Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Research Center for Global Change and Complex Ecosystems, Institute of Eco-Chongming, East China Normal University, Shanghai 200241, China
| | - Jian Zhou
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, State Key Laboratory of Estuarine and Coastal Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- School of Integrative Plant Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Jing Wang
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, State Key Laboratory of Estuarine and Coastal Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Research Center for Global Change and Complex Ecosystems, Institute of Eco-Chongming, East China Normal University, Shanghai 200241, China
| | - Shuli Niu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Yiqi Luo
- School of Integrative Plant Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, 14850, USA
| | - Jianyang Xia
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, State Key Laboratory of Estuarine and Coastal Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
- Research Center for Global Change and Complex Ecosystems, Institute of Eco-Chongming, East China Normal University, Shanghai 200241, China
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Schmiege SC, Heskel M, Fan Y, Way DA. It's only natural: Plant respiration in unmanaged systems. PLANT PHYSIOLOGY 2023; 192:710-727. [PMID: 36943293 PMCID: PMC10231469 DOI: 10.1093/plphys/kiad167] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 06/01/2023]
Abstract
Respiration plays a key role in the terrestrial carbon cycle and is a fundamental metabolic process in all plant tissues and cells. We review respiration from the perspective of plants that grow in their natural habitat and how it is influenced by wide-ranging elements at different scales, from metabolic substrate availability to shifts in climate. Decades of field-based measurements have honed our understanding of the biological and environmental controls on leaf, root, stem, and whole-organism respiration. Despite this effort, there remain gaps in our knowledge within and across species and ecosystems, especially in more challenging-to-measure tissues like roots. Recent databases of respiration rates and associated leaf traits from species representing diverse biomes, plant functional types, and regional climates have allowed for a wider-lens view at modeling this important CO2 flux. We also re-analyze published data sets to show that maximum leaf respiration rates (Rmax) in species from around the globe are related both to leaf economic traits and environmental variables (precipitation and air temperature), but that root respiration does not follow the same latitudinal trends previously published for leaf data. We encourage the ecophysiological community to continue to expand their study of plant respiration in tissues that are difficult to measure and at the whole plant and ecosystem levels to address outstanding questions in the field.
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Affiliation(s)
- Stephanie C Schmiege
- Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biology, Western University, N6A 3K7, London, ON, Canada
| | - Mary Heskel
- Department of Biology, Macalester College, Saint Paul, MN, USA 55105
| | - Yuzhen Fan
- Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Danielle A Way
- Department of Biology, Western University, N6A 3K7, London, ON, Canada
- Research School of Biology, The Australian National University, Acton, ACT, Australia
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, USA
- Nicholas School of the Environment, Duke University, Durham, NC, USA
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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: 5] [Impact Index Per Article: 2.5] [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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Potkay A, Feng X. Do stomata optimize turgor-driven growth? A new framework for integrating stomata response with whole-plant hydraulics and carbon balance. THE NEW PHYTOLOGIST 2023; 238:506-528. [PMID: 36377138 DOI: 10.1111/nph.18620] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
Every existing optimal stomatal model uses photosynthetic carbon assimilation as a proxy for plant evolutionary fitness. However, assimilation and growth are often decoupled, making assimilation less ideal for representing fitness when optimizing stomatal conductance to water vapor and carbon dioxide. Instead, growth should be considered a closer proxy for fitness. We hypothesize stomata have evolved to maximize turgor-driven growth, instead of assimilation, over entire plants' lifetimes, improving their abilities to compete and reproduce. We develop a stomata model that dynamically maximizes whole-stem growth following principles from turgor-driven growth models. Stomata open to assimilate carbohydrates that supply growth and osmotically generate turgor, while stomata close to prevent losses of turgor and growth due to negative water potentials. In steady state, the growth optimization model captures realistic stomatal, growth, and carbohydrate responses to environmental cues, reconciles conflicting interpretations within existing stomatal optimization theories, and explains patterns of carbohydrate storage and xylem conductance observed during and after drought. Our growth optimization hypothesis introduces a new paradigm for stomatal optimization models, elevates the role of whole-plant carbon use and carbon storage in stomatal functioning, and has the potential to simultaneously predict gross productivity, net productivity, and plant mortality through a single, consistent modeling framework.
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Affiliation(s)
- Aaron Potkay
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
| | - Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Twin Cities, Minneapolis, MN, 55455, USA
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8
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Oswald SW, Aubrey DP. Modeling starch dynamics from seasonal variations of photosynthesis, growth, and respiration. TREE PHYSIOLOGY 2023:tpad007. [PMID: 36708035 DOI: 10.1093/treephys/tpad007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 11/21/2022] [Indexed: 06/18/2023]
Abstract
Nonstructural carbohydrates (NSCs) buffer differences in plant carbon supply (photosynthesis) and demand (respiration, growth, etc.) but the regulation of their dynamics remains unresolved. Seasonal variations in NSCs are well-documented, but differences in the time-average, amplitude, phase, and other characteristics across ecosystems and functional types lack explanation; furthermore, observed dynamics do not always match expectations. The failure to match observed and expected dynamics has stimulated debate on whether carbon supply or demand drives NSC dynamics. To gain insight into how carbon supply and demand drive seasonal NSC dynamics, we derive a simple model of NSC dynamics based on carbon mass balance and linearizing the NSC demand to determine how supply-driven and demand-driven seasonal NSC dynamics differ. We find that supply-driven and demand-driven dynamics yield distinct timings of seasonal extrema, and supply overrides demand when carbon supply is low in winter (e.g., at high latitudes). Our results also suggest that NSC dynamics often lag changes carbon mass balance. We also predict differences in NSC dynamics across mass, suggesting saplings are more dynamics and respond faster to the environment than mature trees. Our findings suggest substrate-dependent regulation with environmental variation is sufficient to generate complex NSC dynamics.
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Affiliation(s)
- Scott W Oswald
- Savannah River Ecology Lab, Savannah River Site, Jackson, SC, USA
- Warnell School of Forestry, University of Georgia, Athens, GA, USA
| | - Doug P Aubrey
- Savannah River Ecology Lab, Savannah River Site, Jackson, SC, USA
- Warnell School of Forestry, University of Georgia, Athens, GA, USA
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9
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Crous KY, Uddling J, De Kauwe MG. Temperature responses of photosynthesis and respiration in evergreen trees from boreal to tropical latitudes. THE NEW PHYTOLOGIST 2022; 234:353-374. [PMID: 35007351 PMCID: PMC9994441 DOI: 10.1111/nph.17951] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 12/03/2021] [Indexed: 05/29/2023]
Abstract
Evergreen species are widespread across the globe, representing two major plant functional forms in terrestrial models. We reviewed and analysed the responses of photosynthesis and respiration to warming in 101 evergreen species from boreal to tropical biomes. Summertime temperatures affected both latitudinal gas exchange rates and the degree of responsiveness to experimental warming. The decrease in net photosynthesis at 25°C (Anet25 ) was larger with warming in tropical climates than cooler ones. Respiration at 25°C (R25 ) was reduced by 14% in response to warming across species and biomes. Gymnosperms were more sensitive to greater amounts of warming than broadleaved evergreens, with Anet25 and R25 reduced c. 30-40% with > 10°C warming. While standardised rates of carboxylation (Vcmax25 ) and electron transport (Jmax25 ) adjusted to warming, the magnitude of this adjustment was not related to warming amount (range 0.6-16°C). The temperature optimum of photosynthesis (ToptA ) increased on average 0.34°C per °C warming. The combination of more constrained acclimation of photosynthesis and increasing respiration rates with warming could possibly result in a reduced carbon sink in future warmer climates. The predictable patterns of thermal acclimation across biomes provide a strong basis to improve modelling predictions of the future terrestrial carbon sink with warming.
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Affiliation(s)
- Kristine Y. Crous
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - Johan Uddling
- Department of Biological and Environmental SciencesUniversity of GothenburgPO Box 461GothenburgSE‐405 30Sweden
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