Effects of nitrogen application on physiological traits and photosynthesis of wheat flag leaves

Study was carried out on physiological traits and photosynthesis of flag leaves of Zhengmai 9023. The results indicated that the chlorophyll, nitrogen content and nitrate reductase activity of flag leave of booting--applying treatment were best (60%),Meanwhile, compared to those of complete base-applying,re-growth stages and early jointing-applying treatments, the net photosynthetic rate of wheat was increased by 5.8%, 17.2% and 38.5%, this showed that little applying nitrogen of early stages and more applying nitrogen of later stages both increased chlorophyll,nitrogen content and nitrate reductase activity of flag leaves wheat and improved photosynthetic characteristics and prevented leave premature.