Seasonal variation of key model parameters for gas exchange between wheat and atmosphere at leaf and canopy scales
Starting from the scales of leaves and canopies,this article uses handheld photosynthetic instruments and eddy correlation methods to analyze and determine the seasonal variation characteristics of key parameters in the gas exchange models of C3 crops for spring and winter wheat.Results show that the maximum carboxylation rate and maximum electron transfer rate at the leaf scale of spring wheat decrease rapidly in the late growth stage,with no significant differences in other stages.However,the ratio of the two remained relatively stable with the development period,with an average of 2.2.The slope of the stomatal conductance model for spring wheat leaves during the growing season varies between 9 and 11,with a mean of 9.7.The maximum carboxylation rate and maximum electron transfer rate at the canopy scale of winter wheat exhibit parabolic changes with the development period,but the ratio of the two is relatively stable,with an average of 1.43;the slope of the winter wheat canopy conductance model shows no significant variation in different years and seasons,and fluctuates around the mean of 12 throughout the entire growth period.In this study,the seasonal variation of the parameters that characterize the photosynthetic capacity of crops is demonstrated,and the slope of the stomatal conductance model is relatively stable.This study demonstrates the variation of parameters that characterize crop photosynthetic capacity with growth period and the relatively stable slope of stomatal conductance model.It can provide parameterized basis for the analysis of land atmosphere interaction process and simulation of ecosystem carbon water cycle.
maximum carboxylation rateslope of stomatal conductance modelwheatexchange of carbon and waterphotosynthetic capacity
万方数据
维普
