Abstract:In order to explore the adaptation mechanism of spring wheat in arid oasis region habitat, the photosynthetic response of spring wheat was investigated by six irrigation treatments. The four light response models was comparative analysis, including rectangular hyperbolae model, non-rectangular hyperbolae model, exponential model and correction model of rectangular hyperbolae model. Then the optimal model was selected and the photosynthetic characteristics parameters of spring wheat were calculated by the optimal model with different irrigation schedules. The results showed that the photosynthetic performance of wheat leaves was increased by the increase of irrigation quota, and the photosynthetic performance in early stage of filling was greater than the late stage of filling. There was significant difference between the four light response models in different irrigation quotas. The simulate values of higher irrigation treatments were more accurate than those of lower irrigation treatments by rectangular hyperbolae model, non-rectangular hyperbolae model and exponential model. The correction model ofrectangular hyperbolae model had the maximum simulation accuracy by error tests. So it was optimal model to fit light response curves of spring wheat in desert oasis. The photosynthetic parameters showed that maximum net photosynthesis rate (Pmax), apparent quantum efficiency (Q) and light saturation point (Is) of 420mm treatment were higher than those of others, but the light compensation point (Ic) was decreased significantly. Therefore, the appropriate irrigation treatments can expand the light adaption ranges of spring wheat, improve light energy utilization and promote the increase of yield in desert oasis.
