| In the agricultural production and ecological environment,there are more and more attention with the problem of salinization.There are many land with high concentration of saline-alkali in the arid and semi-arid regions of China.The crop growth environment is harsh.Avena sativa belong to the genus(Avena)Gramineae.Due to high resistance to salt and alkali,oat is widely cultivated as the main food in the arid and semi-arid areas of China.It have important value to study salt and alkali resistance of oats for economy and ecology.Salicylic acid exist in plants.It is able to transmit information during biotic and abiotic stresses,regulate plant physiological mechanisms and protect plants.In this study,we selected two varieties of oats,‘Meng yan1’ and ‘Tai Yang Shen’.To study the effect of SA on photosynthesis,antioxidase,carbohydrate,carbohydrate related enzymes and root of oats at jointing stage and heading stage,0.05 mmol/L and 0.1 mmol/L of SA were applied after the saline-alkali stress.The main findings are as follows:(1)Under salt-alkali stress,the photosynthetic change of oats appeared in the stomatal limitation increasing,the photosynthesis reducing,the cell water loss reducing.In heading stage,the photosynthesis capacity of oats were more serious than that of jointing stage.After applying 0.05 mmol/L of SA,it was able to improve the photosynthesis capacity.The level of 0.1 mmol/L was more serious than that of 0.05 mmol/L.So exogenous SA had better significant effect during jointing stage.The photosynthesis capacity closed to the control group’s level.(2)Under salt-alkali stress,the antioxidase activity of ‘Meng yan 1’ was increased.Under salt stress,the antioxidase activity of ‘Tai Yang Shen’ was decreased due to the salt was a high concentration.The MDA of ‘Meng yan 1’was lower than that of ‘Tai Yang Shen’.Under alkali stress,content of MDA was higher than that of salt stress.At the jointing stage,the antioxidasa activity of ‘Meng yan 1’ was increased to a greater extent.The antioxidase of roots was greater than that in leaves at jointing stage,because roots were more early and sensitive to feel salt-alkali stress.Exogenous SA can increase the antioxidase activity and decrease the content of MDA,it better for oats which that of under alkaline stress.The level of 0.1 mmol/L was more serious than that of 0.05 mmol/L.(3)Under salt-alkali stress,The activity of carbohydrate synthases was increased,and the activity of invertases was decreased.The activity of carbohydrate synthase of ‘Meng yan 1’ was greater increase than that of ‘Tai Yang Shen’.Further carbohydrate were accumulated in the leaves.The carbohydrate of roots were lighter than that of leaves.After applying exogenous 0.05 mmol/L SA,the activity of synthetases was decreased,and the activity of invertases invertases was increased.Carbohydrate was able to be runed out in time.Oats improved osmotic adjustment ability and reduced water loss.It was more effective for roots during jointing stage.The level of0.1 mmol/L was more serious than that of 0.05 mmol/L.(4)Under salt-alkali stress,the weight and volume of root were decreased.Under the salt stress,the root activity was increased.during the jointing stage,the root activity of oats were more higher than that of the heading stage.Under alkali stress,the root activity of oats were decreased.After applying exogenous 0.05 mmol/L SA,the weight and volume of roots were more higher than that of the salt stress.The weight,volume and activity of roots were more higher than that of the alkali stress.It indicated that alkali stress had a great influence on oats,and it was necessary to maintain high root activity to resist stress. |
