Effect Of Different Nitrogen Levels Treatment On Activity And Expression Of Key Enzyme Of Carbon And Nitrogen

Carbon and nitrogen metabolism is the basic material and energy metabolism in plants,which not only affects plant growth and development, but also affect the quality of rice yieldand quality formation. GS and GDH is key enzyme in carbon and nitrogen metabolism, whoseactivity can affect carbon nitrogen balance and the process of carbon and nitrogen metabolism inrice. Our research’s materials are9311and LYP which were treated with three different levels ofnitrogen. Obsevers of the changes of physiology, transcription and protein three respects, our researchfocus on enzymes changes related to carbon and nitrogen metabolism under different nitrogen levelstreatment, especially for GS and GDH, to approach the role of GS and GDH in rice carbon andnitrogen balance and how to maintain the carbon and nitrogen metabolism balance underdifferent nitrogen levels. The experimental results are as follows:1By measuring the activity of amylase, invertases, NR, GS and GDH et al. the date indicated that as the increase of exogenous nitrogen, the inorganic nitrogen content and the activity ofkey enzymes of nitrogen metabolism like NR and GS increasing to play a positive regulatoryrole in nitrogen metabolism, and then to affect plant growth and development. The nitrogen canpromote photosynthetic carbon fixation significantly, weaken the accumulation of metabolic ofcarbohydrates, format nitrogen compounds from a large number of photosynthetic products, sothe activity of key enzymes of carbon metabolism like invertases and amylase increase toaccelerate the conversion of starch and sucrose to provide carbon skeleton for nitrogenmetabolism. Therefore, along with increasing of the amount of nitrogen, the nitrogen metabolismto enhance carbon metabolism will also enhance the of the nitrogen, the nitrogen metabolism theincrease of the amount of nitrogen can enhance the nitrogen metabolism and carbon metabolism.As the difference of nitrogen response mechanism between LYP and9311, they have differenceon nitrogen utilization and LYP have heterosist.2By measuring the expression quantity of GS and GDH isozyme under different nitrogentreatments, we find that Low nitrogen could promote the expression quantity of GS1’s mRNAsignificantly in9311and LYP. GS2plays different roles in9311and LYP, low nitrogen couldpromote the expression quantity of GS2’s mRNA significantly in9311, high nitrogen couldpromote the expression quantity of GS2’s mRNA significantly in LYP. Low nitrogen couldpromote the expression quantity of GDH1’s、 GDH2’s、 GDH3’s and GDH4’s mRNAsignificantly in LYP. High nitrogen could promote the expression quantity of GDH1’s mRNAand inhibit the expression quantity of GDH4’s mRNA. GS and GDH isoenzyme have differentresponse to adapt to outside stress under low nitrogen and high nitrogen treatment. Comparedwith1N, the expression quantity of GS1protein increased under1/4N and2N treatments in9311. The expression quantity of GDH1protein increased under1/4N and decreased in under2N in theLYP. The expression quantity of GS1’s mRNA consistent with protein in9311and LYP while theexpression quantity of GDH1’s mRNA do not consistent with protein. LYP make the appropriateresponse under low nitrogen and high nitrogen treatment and showing heterosis,9311and LYPhave different mechanism of nitrogen utlilization mechanism.