Effect of Different Irrigation Times and Nitrogen Forms on Flag Leaf Senescence and Yield of Winter Wheat Zhengmai 9023

In order to understand the effects of irrigation times and nitrogen forms on chlorophyll content,SOD activities,O.-2 producing rate,net photosynthetic rate of flag leaf of strong gluten wheat zhengmai9023 at grain filling stage and it's yield,a field experiment was conducted at experimental station of College of Agronomy,Henan University of Science and Technology from 2007 to 2009.The results showed that chlorophyll content,SOD activities,net photosynthetic rate of flag leaf could be increased and O.-2 producing rate could be decreased by the increasing of the number of irrigation times,and so the yield increased.NH4-N(NH4HCO3) could rise chlorophyll content at the early filling stage and the net photosynthetic rate of the whole stage of grain filling,reduce the O.-2 producing rate at the later filling stage,so it delayed the senescence of flag leaf and further more increased the yield.In the view of concurrent effects of different irrigation times and nitrogen forms,the treatment of W3N3 was the highest because of it's highest chlorophyll content,SOD activities,net photosynthetic rate and the lowest O.-2 producing rate.Effects of different irrigation times and nitrogen forms on flag leaf senescence and yield of winter wheat Zhengmai9023 were remarkable,and the effect of irrigation times was greater than that of nitrogen forms.