Aims
Prediction of whole-plant short-term water use efficiency (WUEs,P) is essential to indicate plant performance and facilitates comparison across different temporal and spatial scales. Here, the isotope model for WUEs,P was scaled-up from the leaf to the whole-plant level.
Methods
For WUEs,P modelling, leaf gas exchange information, plant respiration and “unproductive” water loss were taken into account. Specifically, in shaping the expression of the WUEs,P, we emphasized the role of both stomatal (gsw) and mesophyll conductance (gm).
Results
The verification showed that estimates of gsw from the coupled photosynthesis (Pn,L)-gsw model accounting for the effect of soil water stress slightly outperformed the model neglecting the soil water status effect, and the established coupled Pn,L-gm model proved more effective in the estimation of gm than the previously proposed model. Introducing the two diffusion control functions into the whole-plant model, the developed model for WUEs,P effectively captured its response pattern to different CO2 concentration (Ca) and soil water content (SWC) conditions.
Conclusions
Overall, this study confirmed that accurate estimation of WUEs,P requires an improved predictive accuracy of gsw and gm. These results have important implications for predicting how plants respond to climate change.