Effects Of Different Nitrogen Application Rates On Distribution And Accumulation Of Nitrogen And Zinc And Grain Quality In Wheat (Triticum Aestivum L.)

In view of the lack of studies on the accumulation and transport of nitrogen and zinc elements from root to overground and the detailed classification of various organs in different growth stages of wheat in recent years,the effects of nitrogen fertilization on the accumulation and distribution of nitrogen and zinc elements and grain quality in different organs of different wheat varieties were discussed,in order to provide theoretical basis for high-yield and efficient cultivation and variety selection.This study was conducted in Yuanyang Science and Education Park（N35.14°,E113.95 °）of Henan Agricultural University.Nitrogen application with three levels in the experiments,namely N1(0kg·hm^-2),N2(135kg·hm^-2),and N3(270kg·hm^-2);Four semi-winter high-yielding cultivars were used as materials,which were C1（Shangmai 156）,C2（Bainong 418）,C3（Bainong 207）and C4（Kaimai 21）,in order to study nitrogen accumulation and zinc accumulation,net absorption and transfer of nitrogen and zinc elements,grain yield and quality,nitrogen use efficiency.The main research results are as follows:（1）The nitrogen accumulation in wheat leaves before flowering and anthesis was the highest,and the nitrogen accumulation in wheat grains from filling stage to maturity stage was the highest.Under different N application conditions,the N accumulation obtained by redistribution in upper,middle and lower panicle parts accounted for 57.80% ～ 62.23%,58.09% ～ 68.07% and 59.81% ～65.32% of the total N accumulation in upper,middle and lower panicle parts,respectively.The contribution of net uptake and accumulation of nitrogen in different organs to grain nitrogen was leaf > stem > glume > root.Nitrogen accumulation was mainly concentrated in roots,leaves,stems,glumes and other organs before anthesis,and transferred to grains after anthesis through redistribution of nitrogen.（2）The zinc accumulation in wheat leaves was the highest before jointing stage,the zinc accumulation in stems was the highest at flowering stage,and the zinc accumulation in grains from filling stage to maturity stage was the highest.There was a synergistic phenomenon between nitrogen accumulation and zinc accumulation in different organs at different growth stages.Under different N application levels,the amount of zinc accumulated by redistribution in upper,middle and lower ear grains accounted for 24.42% ～ 42.00%,22.76% ～38.61%,19.77% ～42.89% of the total amount of zinc accumulated in upper,middle and lower ear grains.The contribution of net absorption and accumulation of zinc in different organs to grain zinc was as follows: stem > glume >root > leaf.Zinc accumulation was mainly concentrated in roots,leaves,stems,glume and other organs in early and middle growth stages,and was transferred to grains by redistribution of zinc in later growth stages.（3）Increased application of nitrogen fertilizer had significant effects on the accumulation of nitrogen and zinc in different organs of wheat at different periods.Compared with N1 without N application,all four wheat varieties increased with the increase of N application.Among the four varieties,the amount of zinc accumulated in different organs of Bainong 207 was higher in different periods,while the amount of zinc accumulated in Bainong 418 was lower.（4）N uptake efficiency,N use efficiency,N harvest index and N partial productivity all showed a downward trend with the increase of N application rate,and the differences among treatments reached a significant level.The N partial productivity and N use efficiency of Kaimai 21 were the highest.In conclusion,increased application of nitrogen fertilizer could increase the accumulation of nitrogen and zinc in different organs of wheat at different stages significantly,and there were significant differences among different varieties.There was a synergistic effect on the accumulation of nitrogen and zinc in different organs of wheat at different stages.The accumulation of zinc was the highest in leaves before jointing stage,the highest in stems at flowering stage,nitrogen accumulation was the highest in leaves before flowering stage,and both the nitrogen and zinc accumulation were the highest in spike at grain filling and maturity stage.