Journal Article

Accounting for mesophyll conductance substantially improves 13 C‐based estimates of intrinsic water‐use efficiency

Wang, Xu Ming, Institut de Recherche en Horticulture et Semences (IRHS) ; Université d'Angers (UA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-INSTITUT AGRO Agrocampus Ouest ; Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), College of Geographical Science, Fujian Normal University, Yang, Yusheng, National Natural Science Foundation of China (NSFC) : NSFC 31870377 ;National Natural Science Foundation of Guangdong Province : 2018A030313450 ;German Research Foundation (DFG) : SCHN 557/7-1 : SCHN 557/9-1, Tcherkez, Guillaume, Gong, Xiao Ying, Technische Universität Munchen - Technical University Munich - Université Technique de Munich (TUM), Schäufele, Rudi, Schnyder, Hans, Ma, Wei Ting

2021

Overview

Carbon isotope discrimination (Delta) has been used widely to infer intrinsic water-use efficiency (iWUE) of C-3 plants, a key parameter linking carbon and water fluxes. Despite the essential role of mesophyll conductance (g(m)) in photosynthesis and Delta, its effect on Delta-based predictions of iWUE has generally been neglected.Here, we derive a mathematical expression of iWUE as a function of Delta that includes g(m) (iWUE(mes)) and exploits the g(m)-stomatal conductance (g(sc)) relationship across drought-stress levels and plant functional groups (deciduous or semideciduous woody, evergreen woody and herbaceous species) in a global database. iWUE(mes) was further validated with an independent dataset of online-Delta and CO2 and H2O gas exchange measurements with seven species.Drought stress reduced g(sc) and g(m) by nearly one-half across all plant functional groups, but had no significant effect on the g(sc) : g(m) ratio, with a well supported value of 0.79 +/- 0.07 (95% CI, n = 198). g(m) was negatively correlated to iWUE. Incorporating the g(sc) : g(m) ratio greatly improved estimates of iWUE, compared with calculations that assumed infinite g(m).The inclusion of the g(sc) : g(m) ratio, fixed at 0.79 when g(m) was unknown, proved desirable to eliminate significant errors in estimating iWUE from Delta across various C-3 vegetation types.

• Publisher: Wiley,HAL CCSD
• Subject: Carbon Dioxide / Life Sciences / Mesophyll Cells / Photosynthesis / Plant Leaves / Plant Stomata / Vegetal Biology / Water
• ISBN: 0005831626000