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Ren W, Tian L, Querejeta JI. Tight coupling between leaf δ 13 C and N content along leaf ageing in the N 2 -fixing legume tree black locust (Robinia pseudoacacia L.). PHYSIOLOGIA PLANTARUM 2024; 176:e14235. [PMID: 38472162 DOI: 10.1111/ppl.14235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 01/29/2024] [Accepted: 02/08/2024] [Indexed: 03/14/2024]
Abstract
N2 -fixing legumes can strongly affect ecosystem functions by supplying nitrogen (N) and improving the carbon-fixing capacity of vegetation. Still, the question of how their leaf-level N status and carbon metabolism are coordinated along leaf ageing remains unexplored. Leaf tissue carbon isotopic composition (δ13 C) provides a useful indicator of time-integrated intrinsic water use efficiency (WUEi). Here, we quantified the seasonal changes of leaf δ13 C, N content on a mass and area basis (Nmass , Narea , respectively), Δ18 O (leaf 18 O enrichment above source water, a proxy of time-integrated stomatal conductance) and morphological traits in an emblematic N2 -fixing legume tree, the black locust (Robinia pseudoacacia L.), at a subtropical site in Southwest China. We also measured xylem, soil and rainwater isotopes (δ18 O, δ2 H) to characterize tree water uptake patterns. Xylem water isotopic data reveal that black locust primarily used shallow soil water in this humid habitat. Black locust exhibited a decreasing δ13 C along leaf ageing, which was largely driven by decreasing leaf Nmass , despite roughly constant Narea . In contrast, the decreasing δ13 C along leaf ageing was largely uncoupled from parallel increases in Δ18 O and leaf thickness. Leaf N content is used as a proxy of leaf photosynthetic capacity; thus, it plays a key role in determining the seasonality in δ13 C, whereas the roles of stomatal conductance and leaf morphology are minor. Black locust leaves can effectively adjust to changing environmental conditions along leaf ageing through LMA increases and moderate stomatal conductance reduction while maintaining constant Narea to optimize photosynthesis and carbon assimilation, despite declining leaf Nmass and δ13 C.
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Affiliation(s)
- Wei Ren
- Institute of International Rivers and Eco-Security, Yunnan University, Kunming, China
- Chongqing Key Laboratory of Karst Environment, School of Geographical Sciences, Southwest University, Chongqing, China
| | - Lide Tian
- Institute of International Rivers and Eco-Security, Yunnan University, Kunming, China
- Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Kunming, China
| | - José Ignacio Querejeta
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS, CSIC), Murcia, Spain
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2
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Yu YZ, Liu HT, Yang F, Li L, Schäufele R, Tcherkez G, Schnyder H, Gong XY. δ13C of bulk organic matter and cellulose reveal post-photosynthetic fractionation during ontogeny in C4 grass leaves. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1451-1464. [PMID: 37943576 DOI: 10.1093/jxb/erad445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
The 13C isotope composition (δ13C) of leaf dry matter is a useful tool for physiological and ecological studies. However, how post-photosynthetic fractionation associated with respiration and carbon export influences δ13C remains uncertain. We investigated the effects of post-photosynthetic fractionation on δ13C of mature leaves of Cleistogenes squarrosa, a perennial C4 grass, in controlled experiments with different levels of vapour pressure deficit and nitrogen supply. With increasing leaf age class, the 12C/13C fractionation of leaf organic matter relative to the δ13C of atmosphere CO2 (ΔDM) increased while that of cellulose (Δcel) was almost constant. The divergence between ΔDM and Δcel increased with leaf age class, with a maximum value of 1.6‰, indicating the accumulation of post-photosynthetic fractionation. Applying a new mass balance model that accounts for respiration and export of photosynthates, we found an apparent 12C/13C fractionation associated with carbon export of -0.5‰ to -1.0‰. Different ΔDM among leaves, pseudostems, daughter tillers, and roots indicate that post-photosynthetic fractionation happens at the whole-plant level. Compared with ΔDM of old leaves, ΔDM of young leaves and Δcel are more reliable proxies for predicting physiological parameters due to the lower sensitivity to post-photosynthetic fractionation and the similar sensitivity in responses to environmental changes.
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Affiliation(s)
- Yong Zhi Yu
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Henan Agricultural University, Zhengzhou 450046, China
| | - Fang Yang
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Jilin Agricultural University, Changchun 130117, China
| | - Lei Li
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Science, Australian National University, Canberra ACT 0200, Australia
- Institut de Recherche en Horticulture et Semences, INRAe, Université d'Angers, 42 rue Georges Morel, 49070 Beaucouzé, France
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Xiao Ying Gong
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, China
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Ubierna N, Holloway-Phillips MM, Wingate L, Ogée J, Busch FA, Farquhar GD. Using Carbon Stable Isotopes to Study C 3 and C 4 Photosynthesis: Models and Calculations. Methods Mol Biol 2024; 2790:163-211. [PMID: 38649572 DOI: 10.1007/978-1-0716-3790-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, laser absorption spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets at lower cost and with unprecedented temporal resolution. More data and accompanying knowledge have permitted refinement of 13C discrimination model equations, but often at the expense of increased model complexity and difficult parametrization. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations available to researchers. We update our previous 2018 version of this chapter by including recently improved descriptions of (photo)respiratory processes and associated fractionations. We discuss the capabilities and limitations of the diverse 13C discrimination model equations and provide guidance for selecting the model complexity needed for different applications.
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Affiliation(s)
- Nerea Ubierna
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Meisha-Marika Holloway-Phillips
- Research Unit of Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmendsorf, Switzerland
| | - Lisa Wingate
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Jérôme Ogée
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Florian A Busch
- School of Biosciences and The Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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Ma WT, Yu YZ, Wang X, Gong XY. Estimation of intrinsic water-use efficiency from δ 13C signature of C 3 leaves: Assumptions and uncertainty. FRONTIERS IN PLANT SCIENCE 2023; 13:1037972. [PMID: 36714771 PMCID: PMC9877432 DOI: 10.3389/fpls.2022.1037972] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
Carbon isotope composition (δ13C) has been widely used to estimate the intrinsic water-use efficiency (iWUE) of plants in ecosystems around the world, providing an ultimate record of the functional response of plants to climate change. This approach relies on established relationships between leaf gas exchange and isotopic discrimination, which are reflected in different formulations of 13C-based iWUE models. In the current literature, most studies have utilized the simple, linear equation of photosynthetic discrimination to estimate iWUE. However, recent studies demonstrated that using this linear model for quantitative studies of iWUE could be problematic. Despite these advances, there is a scarcity of review papers that have comprehensively reviewed the theoretical basis, assumptions, and uncertainty of 13C-based iWUE models. Here, we 1) present the theoretical basis of 13C-based iWUE models: the classical model (iWUEsim), the comprehensive model (iWUEcom), and the model incorporating mesophyll conductance (iWUEmes); 2) discuss the limitations of the widely used iWUEsim model; 3) and make suggestions on the application of the iWUEmes model. Finally, we suggest that a mechanistic understanding of mesophyll conductance associated effects and post-photosynthetic fractionation are the bottlenecks for improving the 13C-based estimation of iWUE.
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Affiliation(s)
- Wei Ting Ma
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Yong Zhi Yu
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Xuming Wang
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou, China
| | - Xiao Ying Gong
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou, China
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, China
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Ubierna N, Holloway‐Phillips M, Farquhar GD. Scaling from fluxes to organic matter: interpreting 13 C isotope ratios of plant material using flux models. THE NEW PHYTOLOGIST 2022; 236:2003-2008. [PMID: 36385264 PMCID: PMC9827853 DOI: 10.1111/nph.18523] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
This article is a Commentary on Leppä et al. (2022), 236: 2044–2060.
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Affiliation(s)
- Nerea Ubierna
- Research School of BiologyThe Australian National UniversityCanberraACT2601Australia
| | | | - Graham D. Farquhar
- Research School of BiologyThe Australian National UniversityCanberraACT2601Australia
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Chi CJE, Zinsmeister D, Lai IL, Chang SC, Kuo YL, Burkhardt J. Aerosol Impacts on Water Relations of Camphor ( Cinnamomum camphora). FRONTIERS IN PLANT SCIENCE 2022; 13:892096. [PMID: 35795349 PMCID: PMC9251497 DOI: 10.3389/fpls.2022.892096] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Major parts of anthropogenic and natural aerosols are hygroscopic and deliquesce at high humidity, particularly when depositing to leaf surfaces close to transpiring stomata. Deliquescence and subsequent salt creep may establish thin, extraordinary pathways into the stomata, which foster stomatal uptake of nutrients and water but may also cause stomatal liquid water loss by wicking. Such additional water loss is not accompanied by a wider stomatal aperture with a larger CO2 influx and hypothetically reduces water use efficiency (WUE). Here, the possible direct impacts of aerosols on physical and physiological parameters of camphor (Cinnamomum camphora) were studied (i) in a greenhouse experiment using aerosol exclusion and (ii) in a field study in Taiwan, comparing trees at two sites with different aerosol regimes. Scanning electron microscopy (SEM) images showed that leaves grown under aerosol exclusion in filtered air (FA) were lacking the amorphous, flat areas that were abundant on leaves grown in ambient air (AA), suggesting salt crusts formed from deliquescent aerosols. Increasing vapor pressure deficit (VPD) resulted in half the Ball-Berry slope and double WUE for AA compared to FA leaves. This apparent contradiction to the wicking hypothesis may be due to the independent, overcompensating effect of stomatal closure in response to VPD, which affects AA more than FA stomata. Compared to leaves in a more polluted region in the Taiwanese Southwest, NaCl aerosols dominated the leaf surface conditions on mature camphor trees in Eastern Taiwan, while the considerably lower contact angles and the 2.5 times higher minimum epidermal conductances might have come from organic surfactants. Interpretations of SEM images from leaf surface microstructures should consider amorphous areas as possible indicators of aerosol deposition and other hygroscopic material. The amount and type of the material determine the resulting impacts on plant water relations, together with the surrounding atmosphere and ecophysiological traits.
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Affiliation(s)
- Chia-Ju Ellen Chi
- Institute of Crop Science and Resource Conservation, University of Bonn, Bonn, Germany
| | - Daniel Zinsmeister
- Institute of Crop Science and Resource Conservation, University of Bonn, Bonn, Germany
| | - I-Ling Lai
- Graduate Institute of Bioresources, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shih-Chieh Chang
- Department of Natural Resources and Environmental Studies, Center for Interdisciplinary Research on Ecology and Sustainability, National Dong Hwa University, Hualien, Taiwan
| | - Yau-Lun Kuo
- Department of Forestry, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Jürgen Burkhardt
- Institute of Crop Science and Resource Conservation, University of Bonn, Bonn, Germany
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Vogado NO, Cheesman AW, Cernusak LA. Delayed greening during leaf expansion under ambient and elevated CO
2
in tropical tree seedlings. AUSTRAL ECOL 2021. [DOI: 10.1111/aec.13139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nara O. Vogado
- Centre for Tropical Environmental and Sustainability Science and College of Science and Engineering James Cook University 14‐88 McGregor Road, Smithfield Queensland Cairns Queensland 4970 Australia
| | - Alexander W. Cheesman
- Centre for Tropical Environmental and Sustainability Science and College of Science and Engineering James Cook University 14‐88 McGregor Road, Smithfield Queensland Cairns Queensland 4970 Australia
- College of Life and Environmental Sciences University of Exeter Exeter UK
| | - Lucas A. Cernusak
- Centre for Tropical Environmental and Sustainability Science and College of Science and Engineering James Cook University 14‐88 McGregor Road, Smithfield Queensland Cairns Queensland 4970 Australia
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Metcalfe JZ. C 3 plant isotopic variability in a boreal mixed woodland: implications for bison and other herbivores. PeerJ 2021; 9:e12167. [PMID: 34631314 PMCID: PMC8466085 DOI: 10.7717/peerj.12167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/26/2021] [Indexed: 11/20/2022] Open
Abstract
Plant isotopic baselines are critical for accurately reconstructing ancient diets and environments and for using stable isotopes to monitor ecosystem conservation. This study examines the stable carbon and nitrogen isotope compositions (δ 13C, δ 15N) of terrestrial C3 plants in Elk Island National Park (EINP), Alberta, Canada, with a focus on plants consumed by grazers. EINP is located in a boreal mixed woodland ecozone close to the transition area between historic wood and plains bison habitats, and is currently home to separate herds of wood and plains bison. For this study, 165 C3 plant samples (grasses, sedges, forbs, shrubs, and horsetail) were collected from three habitat types (open, closed, and wet) during two seasons (summer and fall). There were no statistically significant differences in the δ 13C or δ 15N values of grasses, sedges, shrubs and forbs. On the other hand, plant δ 13C and δ 15N values varied among habitats and plant parts, and the values increased from summer to fall. These results have several implications for interpreting herbivore tissue isotopic compositions: (1) consuming different proportions of grasses, sedges, shrubs, and forbs might not result in isotopic niche partitioning, (2) feeding in different microhabitats or selecting different parts of the same types of plants could result in isotopic niche partitioning, and (3) seasonal isotopic changes in herbivore tissues could reflect seasonal isotopic changes in dietary plants rather than (or in addition to) changes in animal diet or physiology. In addition, the positively skewed plant δ 15N distributions highlight the need for researchers to carefully evaluate the characteristics of their distributions prior to reporting data (e.g., means, standard deviations) or applying statistical models (e.g., parametric tests that assume normality). Overall, this study reiterates the importance of accessing ecosystem-specific isotopic baselines for addressing research questions in archaeology, paleontology, and ecology.
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Affiliation(s)
- Jessica Z Metcalfe
- Department of Anthropology, Lakehead University, Thunder Bay, Ontario, Canada
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Oddo E, D'Asaro G, Monti E, Signa G, Vizzini S, Sajeva M. Carbon and nitrogen isotopic values in Lithops aucampiae during leaf development. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 165:196-199. [PMID: 34051625 DOI: 10.1016/j.plaphy.2021.05.017] [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: 03/19/2021] [Accepted: 05/14/2021] [Indexed: 06/12/2023]
Abstract
Lithops (Aizoaceae) are succulent plants consisting of a pair of opposite succulent leaves inserted on an extremely short stem. The apical meristem produces a new leaf pair that develops between the older pair, recycling water and metabolites. This peculiar anatomy and growth form make ecophysiological studies quite challenging. Lithops are considered to have CAM metabolism, though experimental evidence is scarce. We followed the changes in carbon and nitrogen isotopic values in mature leaves, young leaves and roots, with the aim of investigating how the use of resources is optimized to achieve survival in extremely arid environments. Two-year-old plants of Lithops aucampiae were grown in pots with no irrigation for six months. Plants were sampled periodically, and isotopic values were recorded in relation to the developmental pattern of the leaves. δ13C ranged from -16.4 to -13.1‰ with leaves showing less negative values than roots. δ15N ranged between -0.8 and 3.9‰ with leaves showing higher values than roots. To the best of our knowledge, this is the first experimental evidence of carbon and nitrogen isotope values in Lithops, the former providing evidence for CAM metabolism.
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Affiliation(s)
- Elisabetta Oddo
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Via Archirafi 20, 90123, Palermo, Italy.
| | - Giuseppe D'Asaro
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Via Archirafi 20, 90123, Palermo, Italy
| | - Emmanuele Monti
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Via Archirafi 20, 90123, Palermo, Italy
| | - Geraldina Signa
- Department of Earth and Marine Sciences (DISTEM), University of Palermo, Via Archirafi 18, 90123, Palermo, Italy; Consorzio Nazionale Interuniversitario per le Scienze del Mare, CoNISMa, Piazzale Flaminio 9, 00196, Roma, Italy
| | - Salvatrice Vizzini
- Department of Earth and Marine Sciences (DISTEM), University of Palermo, Via Archirafi 18, 90123, Palermo, Italy; Consorzio Nazionale Interuniversitario per le Scienze del Mare, CoNISMa, Piazzale Flaminio 9, 00196, Roma, Italy
| | - Maurizio Sajeva
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Via Archirafi 20, 90123, Palermo, Italy
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Lavergne A, Sandoval D, Hare VJ, Graven H, Prentice IC. Impacts of soil water stress on the acclimated stomatal limitation of photosynthesis: Insights from stable carbon isotope data. GLOBAL CHANGE BIOLOGY 2020; 26:7158-7172. [PMID: 32970907 DOI: 10.1111/gcb.15364] [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: 05/11/2020] [Accepted: 09/15/2020] [Indexed: 05/08/2023]
Abstract
Atmospheric aridity and drought both influence physiological function in plant leaves, but their relative contributions to changes in the ratio of leaf internal to ambient partial pressure of CO2 (χ) - an index of adjustments in both stomatal conductance and photosynthetic rate to environmental conditions - are difficult to disentangle. Many stomatal models predicting χ include the influence of only one of these drivers. In particular, the least-cost optimality hypothesis considers the effect of atmospheric demand for water on χ but does not predict how soils with reduced water further influence χ, potentially leading to an overestimation of χ under dry conditions. Here, we use a large network of stable carbon isotope measurements in C3 woody plants to examine the acclimated response of χ to soil water stress. We estimate the ratio of cost factors for carboxylation and transpiration (β) expected from the theory to explain the variance in the data, and investigate the responses of β (and thus χ) to soil water content and suction across seed plant groups, leaf phenological types and regions. Overall, β decreases linearly with soil drying, implying that the cost of water transport along the soil-plant-atmosphere continuum increases as water available in the soil decreases. However, despite contrasting hydraulic strategies, the stomatal responses of angiosperms and gymnosperms to soil water tend to converge, consistent with the optimality theory. The prediction of β as a simple, empirical function of soil water significantly improves χ predictions by up to 6.3 ± 2.3% (mean ± SD of adjusted-R2 ) over 1980-2018 and results in a reduction of around 2% of mean χ values across the globe. Our results highlight the importance of soil water status on stomatal functions and plant water-use efficiency, and suggest the implementation of trait-based hydraulic functions into the model to account for soil water stress.
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Affiliation(s)
- Aliénor Lavergne
- Carbon Cycle Research Group, Space and Atmospheric Physics, Department of Physics, Imperial College London, London, UK
| | - David Sandoval
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - Vincent J Hare
- Carbon Cycle Research Group, Space and Atmospheric Physics, Department of Physics, Imperial College London, London, UK
- Stable Light Isotope Laboratory, University of Cape Town, Cape Town, South Africa
| | - Heather Graven
- Carbon Cycle Research Group, Space and Atmospheric Physics, Department of Physics, Imperial College London, London, UK
- Grantham Institute - Climate Change and the Environment, Imperial College London, London, UK
| | - Iain Colin Prentice
- Department of Life Sciences, Imperial College London, Ascot, UK
- Grantham Institute - Climate Change and the Environment, Imperial College London, London, UK
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
- Department of Earth System Science, Tsinghua University, Beijing, China
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