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What plant hydraulicscan tell us aboutresponses toclimate‐changedroughts John S. SperryDavid M. Love2015 год

What plant hydraulics can tell us about responses to climate‐change droughts
review

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Аннотация: Summary Climate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard to anticipate because canopy transpiration and diffusive conductance ( G ) respond to drying soil and vapor pressure deficit ( D ) in complex ways. A growing database of hydraulic traits, combined with a parsimonious theory of tree water transport and its regulation, may improve predictions of at‐risk vegetation. The theory uses the physics of flow through soil and xylem to quantify how canopy water supply declines with drought and ceases by hydraulic failure. This transpiration ‘supply function’ is used to predict a water ‘loss function’ by assuming that stomatal regulation exploits transport capacity while avoiding failure. Supply–loss theory incorporates root distribution, hydraulic redistribution, cavitation vulnerability, and cavitation reversal. The theory efficiently defines stomatal responses to D , drying soil, and hydraulic vulnerability. Driving the theory with climate predicts drought‐induced loss of plant hydraulic conductance ( k ), canopy G , carbon assimilation, and productivity. Data lead to the ‘chronic stress hypothesis’ wherein > 60% loss of k increases mortality by multiple mechanisms. Supply–loss theory predicts the climatic conditions that push vegetation over this risk threshold. The theory's simplicity and predictive power encourage testing and application in large‐scale modeling. Contents Summary 14 I. Introduction 14 II. The transpiration supply function 15 III. The transpiration loss function 17 IV. General properties of the supply–loss theory 19 V. Variations on the theme 19 VI. Predicting responses to climate 21 VII. Implications for productivity and mortality: the chronic stress hypothesis 22 VIII. Conclusion 24 Acknowledgements 24 References 24
Год издания: 2015
Авторы: John S. Sperry, David M. Love
Издательство: Wiley
Источник: New Phytologist
Ключевые слова: Plant Water Relations and Carbon Dynamics, Tree-ring climate responses, Forest ecology and management
Другие ссылки: New Phytologist (HTML)
PubMed (HTML)