Response Of Maize Seedlings To Salinization Stress And Its Regulation By Betaine

Using hydroponic method to study the physiological and biochemical characteristics of different maizeseedlings which including protected enzyme activity,lipid peroxidation,osmotic adjustment content, absorptionand transport of ion,photosynthetic characteristics under different salt stress and alkaline stress concentrationand time treatment,in order to analysis the mechanism of injury and salinity tolerance.We also studied thealleviative effect of exogenous betaine on the physiological and biochemical characteristics of different maizeseedlings under different stress time of NaCl stress treatment, discussed the mechanisms of enhance salttolerance about exogenous betaine. The results were obtained as follows:1. Effect on physiological characteristics of different maize genotypes under salt and alkaline stressWith the degree of stress strengthening, the protected enzyme activity content of soluble sugar andsoluble protein content of different maize seedlings increased at first then reduced, while the content of MDAand proline in seedlings and roots firstly decreased then increased; the content of K⁺changed earlier than Na⁺,the ratio of Na⁺/K⁺firstly decreased then increased;the content of net photosynthesis, transpiration rate,stomatal conductance were reduced,the concentration of intercellular CO2first decreased then increased.Themaize genotypes resistant mechanism makes itself less affected than salinity stress on sensitive maize varietiesunder transient salinity stress conditions.2. Alleviative effect of exogenous betaine on different maize genotypes under salt stressExogenous betaine increased the content of total chlorophyll in leaf, activity of prote effect of betainwhen its time treatment at24h and concentration at5mmol·L^-1. Exogenous betaine on different maizeseedlings mitigation of different functions,the mitigation of salt-sensitive maize varieties better than Salinitymaize.