Interspecific variation in the temperature response of mesophyll conductance is related to leaf anatomy
Guanjun Huang, Qiangqiang Zhang, Yuhan Yang, Yu Shu, Xifeng Ren, Shaobing Peng, Yong Li
Abstract
SUMMARY Although mesophyll conductance ( g m ) is known to be sensitive to temperature ( T ), the mechanisms underlying the temperature response of g m are not fully understood. In particular, it has yet to be established whether interspecific variation in g m – T relationships is associated with mesophyll anatomy and vein traits. In the present study, we measured the short‐term response of g m in eight crop species, and leaf water potential ( Ψ leaf ) in five crop species over a temperature range of 15–35°C. The considered structural parameters are surface areas of mesophyll cells and chloroplasts facing intercellular airspaces per unit leaf area ( S m and S c ), cell wall thickness ( T cw ), and vein length per area (VLA). We detected large interspecific variations in the temperature responses of g m and Ψ leaf . The activation energy for g m ( E a,gm ) was found to be positively correlated with S c , although it showed no correlation with T cw . In contrast, VLA was positively correlated with the slope of the linear model of Ψ leaf – T ( a ), whereas E a,gm was marginally correlated with VLA and a . A two‐component model was subsequently used to model g m – T relationships, and the mechanisms underlying the temperature response of g m are discussed. The data presented here indicate that leaf anatomy is a major determinant of the interspecific variation in g m – T relationships.