Study On Resistance Of Tobacco Seedlings Against Low Potassium Stress And Drought Stress Induced By Theanine

Theanine is a non-protein amino acid specifically found in green tea that is good for people's health and induce animal against abiotic stress,but there has noon report about application of exogenous Theanine in plant.The paper studied on the influence of resistance in tobacco seedlings against low potassium stress and drought stress by Theanine.Yunyan 87 as materials,related physiological indexes,the concentration of ions and the expression of related genes was measured.The results were as follows:1.The inhibition on the growth of tobacco seedlings under low potassium stress was alleviated when treated in 0.1 mmol/L and 0.2 mmol/L Theanine,the alleviated effect showed in the growth of tobacco seedlings was promoted and the fresh weight,root length and the content of Chlorophyll of tobacco seedlings was increased.2.The content of GSH and the activities of antioxidant enzymes(POD,CAT,APX)was increased when the tobacco seedlings was treated in 0.1 mmol/L and 0.2 mmol/L Theanine,and the content of H2O2,MDA and soluble protein was decreased,all of the above indicated that 0.1 mmol/L and 0.2 mmol/L Theanine relieved oxidative damage in the producing of ROS induced by low potassium stress in tobacco seedlings.3.The expression of Potassium up-taking related genes was induced and the expression of NTKC and NTKT1 genes was increased when treated in 0.1 mmol/L and 0.2 mmol/L Theanine,the expression of NTLKS1 was increased also when treated in 0.2 mmol/L Theanine,consequently Theanine promoted the absorption of potassium ions in tobacco seedlings.4.The ability of defensing drought stress was increased significantly in tobacco seedlings when treated in 0.25 mmol/LTheanine.It indicated that 0.25 mmol/L Theanine improved the drought tolerance of tobacoo seedlings and protected the growth of tobacco seedlings.5.The content of GSH,the activities of APX and POD was increased and the antioxidant capacity was improved to decrease the accumulation of H2O2 when treated in 0.25 mmol/L Theanine.And 0.25 mmol/L Theanine relieved the damage of oxidation in membrane and osmotic stress which caused by drought stress and protected the structure and function of cell membrane of tobacco seedlings,the relative conductivity,the content of MDA,soluble protein and proline was decreased as a result.In conclusion,the above evidences suggest that Theanine promoted the growth of tobacco seedlings,increased the expression of Potassium up-taking related genes and motivated the antioxidant system to induce tobacco seedlings against low potassium stress.On the other hand,the activity of antioxidant enzymes and antioxidant capacity was increased by Theanine to relieve membrane's oxidation and osmotic stress caused by drought stress,and the resistance in tobacco seedlings against drought stress was improved.