Effect of Different Nitrogen Application on the Physiological Activity of Flag Leaf at the Later Stage of Wheat

The relationship between nitrogen application at different stages and the physiological activity of flag leaf of super high yielding wheat at the later stage was studied. The results showed that the activity of superoxide dismatase (sod) and chlorophyll content in flag leaf decreased in later period, while the membrane lipid peroxidation MDA and relative conductivity declined to increase. Nitrogen application appropriately at connective stage could suppress chlorophyll's degrading, keep the activity of SOD at high level, and decrease membrane lipid peroxidation level, prolong the functional stage of the leaf.