Photosynthetic characteristics and photosynthesis-light response curve models of summer maize

Abstract

Aim: The photosynthesis-light response curve is the most commonly used method to explore the relationship between photosynthetically active radiation and the net photosynthetic rate, because it is more effective to reflect the plant photosynthetic characteristics. And it is very meaningful for researchers to choose a suitable summer corn (Zea mays) photosynthetic model and optimal the models of photosynthesis-light response curve by analyzing the differences between simulation and observation in each growth period of some plant. So the object of this paper was to propose some useful suggestions for the choice of summer corn photosynthetic modes and the optimization of the photosynthetic light response curves model in further. Methods: In this paper, three typical photosynthetic models were used to fitting the photosynthetic light response curve for upper leaf, leaf at ear of grain and lower leaf of summer corn during bell and milk period. And then the fitting degree of each model was compared to the measured data. Photosynthetic active radiation was divided into three parts, and the fitting residual errors of these three models were analyzed individually. Important findings: The photosynthetic characteristic parameters such as maximum net photosynthetic rate (Pnmax), saturated light intensity (Isat) and dark respiration rate (Rd) decreased constantly with a top-down leaf position and the parameters at milk stage were generally lower than the bell stage. Each growth period and leaf position could fit the curve, but some deviation exists for the Pnmax and Isat in the rectangular hyperbolic model and the non-rectangular hyperbolic model. The results of curve fitting residual showed that the simulation values from Ye Zi-Piao model were closest to the actual values, and especially for the high photosynthetically active radiation section.