Interactive Effects Of Light Condition And Nitrogen Supply On Carbon-Nitrogen Metabolism And Growth And Yield Of Gangyou 527

Light and nitrogen can adjust carbon-nitrogen metabolism of rice and coordinate the relationship between vegetative and reproductive growth.They are core factors to affect the growth and the yield of rice.During the growth period of turning green to heading for light and nitrogen treatment,it is significant by using Gangyou 527 as tested material in the experiment to test the interactive effects of light condition,nitrogen supply on carbon-nitrogen metabolism,growth,development,dry matter production,distribution,yield components,and yield-related of the rice.The experimental treatments applied in a split plot design included:two lights(L1:natural light,L2:shade 50%)and five nitrogen levels(NO:0 kg/hm2,N1:60 kg/hm2,N2:120 kg/hm2,N3:180 kg/hm2,N4:240 kg/hm2).The main results are listed as follows:1.Lower light and nitrogen fertilizer can increase the chlorophyll content of rice leaves,but the light and nitrogen fertilizer have distinct synergistic effect on chlorophyll content of rice leaf in tillering stage,jointing stage and mature stage,respectively.Shading the light will decrease the maximal photochemical efficiency.However,if it is under the strong light,more nitrogen will also reduce the actual photochemical efficiency through electron transfer activity.The interactive effect between light condition and nitrogen supply on actual photochemical efficiency of the heat has a dissipation capability significant influence.As a result,light and nitrogen have positive impact on heat dissipation capability of actual photochemical efficiency.Weak light will reduce the leaf photosynthetic rate of rice and the intensity of nitrogen has significant effects on photosynthetic rate.At booting stage,interactive effect of light intensity and nitrogen supply on carbon nitrogen ratio of rice reached extremely significant level.In addition,increasing applied nitrogen fertilizer may decrease anthocyan in content.2.Nitrogen fertilization will increase the soluble protein contents,shading will significantly reduce GS activity,and increasing the amount of nitrogen in blackout conditions will also reduce the GS activity.Rice leaf nitrogen content will increase in a higher nitrogen rate and light shading process.At boom stage,the impact of light and fertilizer on nitrogen content of rice leaf is extremely significant.Because,shading and increasing nitrogen can increase the amount of nitrogen translocation in the leaf and stem,nitrogen harvest index shows a trend of first increasing and then decreasing with the increased nitrogen.The regression analysis shows that when nitrogen is 60kg/hm2 nitrogen,harvest index is the highest under shading conditions.While when nitrogen is 102.5kg/hm2 nitrogen,the harvest index is the highest in natural light conditions.In booting,the range of heading and maturity appropriate carbon nitrogen ratio is between 2.94～3.32,3.38～3.72,5.13～5.46 under shading,and between 2.32～3.03,2.52～2.92,3.54～4.52 under natural light.3.Tiller number will increase in a certain level of time,and then it will have a trend to decrease.As shading and excess nitrogen will delayed the rice tillering.The maximized tillering stage appeared at 28d and 42d after transplanting under natural light and shading,respectively.Shading will reduce spike primary branches and spikelets,and when tiller number decreases,interaction between light and nitrogen on the secondary branch will be active.Increasing the amount of nitrogen as well asstrengthening the light can increase rice dry matter accumulation,and then the influence of nitrogen and light on dry matter in each period will reach to a significant level.Except for the booting stage,light and nitrogen interaction will have significant effects on the dry matter accumulation of rice.More specifically,higher nitrogen contentis only useful to increase the dry matter accumulation under bright light conditions in a later growth period other than an earlier time.4.With the increase of nitrogen amount,the effective panicle number increases at first and then decreased under the shading.As the impact of light and nitrogen on grain number per spike of rice is different in different period,reduction of nitrogen fertilizer can increase the graining number,grain weight,and the seed rate under shading.Light shielding significantly reduces the actual yield of rice,with the increasing nitrogenfertilizer,the rice yields will rise to a peak and then tend to drop.As a result,in this experiment,the production reaches a maximum amount in natural light with 180 kg/hm2 nitrogen level while under fixed lighting conditions,rice yield and nitrogen regression analysis found that under light shading condition,the rice yield can be presented by an equation:y=-0.035x2+3.477x+8062.When nitrogen application amount is 49.67kg/hm2,the highest rice yield can be obtained by 8178.4kg/hm2.Under natural light conditions,the equation of the yield is:y=-0.122x2+32.55x+7090,when the amount of nitrogen is 133.4kg/hm2,the highest rice yield will be obtained by 9261.1 kg/hm2.