Abstract: In order to reveal applicability of different photosynthetic light response models for tobacco, the light response curves of net photosynthetic rates of K326, which treated with 20℃, 30℃ and 35℃ in Zhaowei base in Yuxi, and Honghuadajinyuan (Hongda), KRK26 and Yunyan99, which in natural conditions in Zhaotong, were determined respectively. The photosynthetic light-response curves were simulated by rectangular hyperbolae model, non rectangular hyperbolae model, exponential model, kinetics model and a new model. The results showed that the new model simulated well to light-response curves of light saturation, non light saturation and light inhibition, exponential model simulated well to light saturated response curve, and other three models could not simulated to any light-response curves. The maximum net photosynthetic rates (Pmax) of exponential model and new model were closed to measured values, Pmax of the other three models was higher than measured values, obviously in non rectangular hyperbolae model. Apparent quantum yield (α) of rectangular hyperbolae model and non rectangular hyperbolae model was closed to or exceed than the theoretical value range of maximum quantum yield. α value of exponential model and new model was in normal range, while that of kinetic model was lower. Light component point (Ic) of the models were close to measured values except non rectangular hyperbolae model, which was lower than measured values. Rectangular hyperbolae model, non rectangular hyperbolae model and kinetic model could not use for calculating light saturation point (Is) directly. All the Is of new model were close to measured values. When there were light saturation and light inhibition, Is of exponential model was close to measured value as well. The results indicated that the new model was reasonable for simulating tobacco light response curve.

Key words: Photosynthesis, Light response model, Tobacco, Applicability