Effect of nitrogen forms on the activities of several key enzyme for flue cured tobacco of Yanbian

Selecting flue cured tobacco variety Jiyan 9 to be the material,studied the influence of different nitrogen forms and proportion on protective enzymes(SOD,CAT,MDA) NR,invertase of flue-cured tobacco in the eastern region of Jilin Province through filed experiment.The results showed that in the antioxidant enzymes,the change of the activity of SOD and CAT in different organs of the tobacco leaves,the upper leaves are the highest,follwed by middle and lower leaves.On the MDA,the size in different organs of the tobacco leaves,the lower leaves are the highest,follwed by middle and upper leaves.Compared among the treatments,treatment C(50%: 50%) in the antioxidant enzymes are higher than other treatments,and MDA content is lower than other treatments.It shows that the resistance of treatment C is the strongest,followed by treatment D,B.In the INV,NR and INV/NR,the enzyme activity of INV,NR in different leaves organs is the upper leaves are the highest,follwed by middle and lower leaves,it emerged single peak curve for increased first and then decreased as ammonium nitrogen decreased and nitrate nitrogen increased,the highest value is when it reached 50%:50%,it shows that the appropriate NH4/NO3-ratio can enhance resistance of plant,and promote the carbon-nitrogen metabolism of plant.