6-苄氨基嘌呤（6-BA）对不同氮素水平下玉米叶片衰老过程中光系统II性能的调控效应

A two years experiment was conducted using maize inbred line Qi 319 with different nitrogen fertilization levels and exogenous hormone 6 benzyl adenine (6-BA) treatments. The results demonstrated that the chlorophyll content and net photosyn- thetic rate (Pn) were gradually decreased after anthesis. In treatments of 6-BA without nitrogen fertilizer, chlorophyll contents were increased significantly, but P n showed no significant increase, and the activity of PSII reaction center was not increased. Under the condition of applying nitrogen fertilizer, P n and the activity of PSII reaction center were increased significantly, and based on nitrogen fertilizer used, the 6-BA could improve the response of P n and performance of PSII to nitrogen fertilizer effectively. Under the nitrogen fertilizer and 6-BA interaction conditions, the chlorophyll content and P n were increased significantly (P0.05), the activities of donor site and acceptor site of PSII were increased significantly, and the donor site was improved more than that of acceptor site. The most obvious improvement of the activity of PSII reaction center was appeared at the 10th day after anthesis. The improvement of photosynthetic performance significantly improved the single plant dry matter accumulation and grain yield (P0.05). In conclusion, spraying plant with 6-BA under suitable application of nitrogen fertilizer can significantly improve the photosynthetic performance of maize leaf.