Effect Of Nitrogen Supply On Grain Filling And Material Metabolism In Maize With Different Nitrogen Efficiency

As one of the three most universal food crops in the world,the corn is not ony theimportant food and economical crops,but also plays a decesive role in other industries such aschemical engineering,fuel,medicine and so on.Crops planting has achieved great developmentin last ten years.Improvement of crops yield owes most to the chemical fertilizerapplication,however,the increasement of the crops yield can not keep up with the one ofnitrogen supplication,whice is the most important element fot the crops,especially acts as acrucial role in the stage of grain filling.Although nitrogen almost controls the cropsyield,the differences of nitrogen efficiency genes decides various demands for the nitrogenwhich differs from each other.Reasonable nitrogen application can not only improve the cropsyield in most degree,but can avoid pollutiong the environment.The purpose of the experimentis to research the effect of nitrogen supply on grain filling and material metabolism in maizewith different nitrogen efficiency.From the experiment,we can acqure some conclsions:1Dry matters of the corn grain continues increasing in the grain filling stage wih thegrowing progress,and the devolpment of the grains under the condition of nitrogensupplication behaves better than that with no nitrogen supplication,grains at the bottomposition grows better than the ones at the top position,which implies that grains at the bottom get more advantage in absorbing nutrient than the ones at the top,and the fomer producesinhibition to the latter.2The development advantage of the corn grains in different levels of nitrogensupplication differs in breed:grains of TY presents N2＞N1>N0,LY presents N1＞N2＞N0,XY presents N2＞N1＞N0.3The grain filling rate presents in coordination with nitrogen and starch accumulationrates.Nitrogen supplication can improve the gain filling rate,wich promotes the nitrogen andstarch accumulation rates to.4The grain volume increasement rate presents in coordination with nitrogen and starchaccumulation rates,which indicates that expending the volume could promote theaccumulation of nitrogen and starch and provide sufficient space for the grains to obsorbnutrients better.5The grains’ soluble sugar and sucrose content increase first and then fall in the grainfilling stage,and they tend to keep in coordination in the late period as the sucrose graduallyturns into the main forms of soluble sugar.The soluble sugar content keep in coordinationwith starch:the latter content improves obviously when the former one reaches the maximumrate or falls behind a little,indicating that sufficient sucrose accumulation is the basis of starchcomposition.6Compared in breed for the advantage of dry matters,grains of LY at the top positiongrew best in2013,then followed TY,advantage of XY behaved least,N2was better thanN1;for the grains at the bottom in2013,LY behaved best,then followed XY,TY was the finalone,however,TY behaved better than XY in starch accumulation.Both of the grains at the top and bottom position presented the advantage order in2014:TY,LY,XY.Grains of XY-N1behaved better than the ones of N2in nitrogen accumulation,while the ones of N2did betterthan those of N1in starch accumulation.Different advantage orders perhaps had somethingwith the different levels of nitrogen supplication in two years.7Compared in breed for the difference values’advantage of dry matters in differentlevels of nitrogen supplication,values of grains in nitrogen supplication minus those with nonitrogen and for the grains at the top positon,the order of advantage is LY,TY,XY,and N2inXY was better than N1.For the grains at the bottom position,LY and TY almost behaved sameadvantage,XY presented least advantage.8Compared in breed for the difference values between different positons,XY’values waslargest,TY and LY had little difference.Combined with the advantage of dry matters inbreed,grains of XY at the top position behaved poorest,indicating the possibility of inhibitioneffect from the grains at the bottom position,which may be the reason why the differencevalue of XY is the biggest one.Grains at the top position had big risk of abortion.