Coupled model of stomatal conductance–photosynthesis–transpiration for paddy rice under water-saving irrigation

Abstract

To improve the performance of a coupled model based on a Leuning–Ball stomatal conductance (g_s) model for rice under water deficit conditions, leaf temperature rising (ΔT) was incorporated into the Leuning–Ball model and a revised coupled model for simulation of stomatal conductance g_s–net photosynthesis rate (P_n)–transpiration rate (T_r) was developed based on data collected from a rice paddy with nonflooded controlled irrigation in 2003 and 2004. Both a Leuning–Ball and revised Leuning–Ball and coupled model based on both were evaluated with internal conductance (g_ic) determined by different equations. The performance of the Leuning–Ball model was improved under water deficit condition by incorporating ΔT, and the revised Leuning–Ball model performed better than the Leuning–Ball model in the coupled model of stomatal conductance–photosynthesis–transpiration for rice under water deficit conditions. Meanwhile, accuracy in g_ic calculation is essential for simulation of P_n, but not for simulation of T_r. Thus, leaf temperature rising ΔT is suitable as a leaf water status indicator in a simulation of rice leaf gas exchange response to water deficit conditions.

Keywords:

• stomatal conductance
• net photosynthesis rate
• transpiration rate
• leaf temperature rising
• water deficit

Acknowledgements

This research work was supported by National Natural Science Foundation of China (No. 50839002, 50809022), the Fundamental Research Funds for the Central Universities (No. 2012B07514), and the Qinglan Project of Jiangsu Province.