Study On Basic Regulation Of Nitrogen Assimilation Meitabolism In Different Types Of Spring Maize And Adjustment Of Nitrogen Fertilazer

This experiment utilized different types of spring maize (good quality protein maize LG2, common maize DN250 and high starch maize SD19) as material, studied the absorption and distribution of nitrogen in vegetative parts of maize at different nitrogen levels; profound studied the accumulation regulation of spring maize grains and Amino Acid; discussed the adjustment of nitrogen at enzyme level, so it can rich he physiological basis of spring maize and provide theory basis of using N fertilizer for higher yield and excellent quality of spring maize. The main experiment result are as follows:1. Nitrogen content in different parts changed at different nitrogen levels. In vegetative period ,the content order was leaf>stem>Ieaf sheath and in generative period the order was grain>leaf>stem>leaf sheath>bract> spike-stalk.LG2 each treatment has higher total nitrogen content than DN250 and SD19. Nitrogen distribution center was changed with the changing of growing center. The main distribution of nitrogen was in leaf, stem and leaf sheath before silking stage ,then turn to female inflorescence of maize, after silking stage the grain became the center of nitrogen distribution. The content of nitrogen distribution was grain>leaf>stem> leaf sheath during mature stage ,and in grains which was changed with different varieties. 2.Total chlorophyll content changed with different varieties and nitrogen levels. The order of SD19 was N100>N200>N300>NO, DN250 was N200> N300>N100>NO and LG2 was N300>N100> N200> NO.3.Accumulation of dry matter in leaf, stem and leaf sheath was up to the peak at filling stage and decreased at mature stage to each varieties and treatments, among which is higher nitrogen treatment accumulated fast and performance higher content. For each varieties and treatments the content order was N200 >N300 >N100 >N0. Total dry matter accumulation was enhancing gradually in the whole growth stage and up to the peak at mature period then maintain stable and decreased somehow.4.Nitrogen nutrition level has some influence on the growth and development of spring maize leaves. In the former growing period ,the effect of higher nitrogen treatment was bigger than lower one for DN250 and LG2,whereas SD19 was N200 treatment in the highest level. 5. The activity of NR and GS was changed with different nitrogen levels and presented a single peak curve at the whole growth stage and the order of different varieties of spring maize was N300>N200>N100>N0.6.Protein content of spring maize grains fell gradually after silking stage and rapidly from the 7th day to 21st day. The rate of protein accumulation in grains was relative in the 14th day after silking stage, then went up from 21st day after silking . Each varieties and treatments presented double peak curve except LG2 N200and N300 treatments.The dynamic change of accumulation of Lys in grains was the same as the one of protein and changed with different nitrogen levels . Each varieties and treatments presented double peak curve. The content of Trpfell with the maturing of grains to each varieties at different nitrogen levels.LG2 has higher Trp content and increased with nitrogen increasing. The order of Trp content was N300>N200>N100>N0.7.Different nitrogen level has different effect on yield properties .The hundred - grain weight increased with the increasing nitrogen content. The effect of different nitrogen levels to single plant yield increased with the increasing of nitrogen levels for each varieties. The changing between N300 and N200 was not significant but has extremely notable difference with N100and NO. The protein content for each varieties was the highest at the level of N300.The grain protein content of LG2 was highest but DN250 and SD19 has little difference.