Scaling Up from Leaf to Whole-Plant Level for Water Use Efficiency Estimates Based on Stomatal and Mesophyll Behaviour in Platycladus orientalis

Abstract

Prediction of whole-plant short-term water use efficiency (WUEs,P) is essential to indicate plant performance and facilitate comparison across different temporal and spatial scales. In this study, an isotope model was scaled up from the leaf to the whole-plant level, in order to simulate the variation in WUEs,P in response to different CO2 concentrations (Ca; 400, 600, and 800 μmol·mol−1) and soil water content (SWC; 35–100% of field capacity). 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). Simulations were compared with the measured results to check the model’s applicability. 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. The established coupled Pn,L-gm model also proved more effective in estimating 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 Ca and SWC conditions. Overall, this study confirmed that the 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.

Plant phenotyping relevance

葉から個体全体への水利用効率推定モデルを開発し、実測値との比較で適用性を検証しており、植物の生理形質推定法が研究の中心です。

Code and data availability

The supplied blocks describe a greenhouse/growth-chamber gas-exchange and isotope study with model equations and results, but contain no data availability statement, no public phenotype dataset, no deposited images or sensor data, and no author code/model repository with a public URL. No paper-specific public asset is

No evidence-backed public reproduction asset is currently recorded.