Scaling-up From Leaf to Whole-plant Level for Water Use Efficiency Estimates Based on Stomatal and Mesophyll Behavior

Abstract

Abstract AimsPrediction of whole-plant short-term water use efficiency (WUE s,P ) is essential to indicate plant performance and facilitates comparison across different temporal and spatial scales. Here, the isotope model for WUE s,P was scaled-up from the leaf to the whole-plant level.MethodsFor WUE s,P modelling, leaf gas exchange information, plant respiration and “unproductive” water loss were taken into account. Specifically, in shaping the expression of the WUE s,P , we emphasized the role of both stomatal ( g sw ) and mesophyll conductance ( g m ). ResultsThe verification showed that estimates of g sw from the coupled photosynthesis ( P n,L )- g sw model accounting for the effect of soil water stress slightly outperformed the model neglecting the soil water status effect, and the established coupled P n,L - g m model proved more effective in the estimation of g m than the previously proposed model. Introducing the two diffusion control functions into the whole-plant model, the developed model for WUE s,P effectively captured its response pattern to different CO 2 concentration ( C a ) and soil water content (SWC) conditions. ConclusionsOverall, this study confirmed that accurate estimation of WUE s,P requires an improved predictive accuracy of g sw and g m . These results have important implications for predicting how plants respond to climate change.

Code and data availability

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