Effect of Different Nitrogen Levels on Leaf Senescence of the Japonica Hybrid Rice Dianza 35

The hybrid rice dianza 35 treated as the tested materials to study the effects of different nitrogen levels on leaf senescence.The results showed that with the increase of nitrogen levels,the chlorophyll content,leaf area,photosynthetic rate,the activities of superoxide dismutase(SOD) and peroxidase(POD) of dianza 35 increased significantly,while the content of malondialdehyde(MDA) decreased significantly.Therefore,the leaf senescence was relatively slower,sequentially,improved the efficiency of nitrogen absorption and utilization.Nitrogen also increased dianza 35 plant height,effective panicle,ear length,1000-grain weight,seed setting rate.The amount of 1.6 g of nitrogen was the best nitrogen level,in which the photosynthetic rate,1000-grain weight,seed setting rate were higher,while leaf senescence speed was the slowest.