Effect Of Exogenously Spermine On The Protective Enzyme Of Alfalfa Seedlings Under Water Stress And Studies On Seed Coating Formulation Of Drought Resistance

The paper is composed of two part with the alfalfa seedlings as tested materials.The first part studied the effect of exogenously spermine on the protective enzyme system under water stress in order to exam the relationship between the exogenously polyamine and the drought tolerance of alfalfa seedlings.The results showed that pretreatment with the different density of exogenously Spermine increased the drought tolerance of alfalfa seedlings by conducting water stress of artificial modeling using polyethylene giycoi (PEG-6000).Every treatment be compared with the CK, the contents of MDA deceased, the activities of SOD. POD and CAT increased. With increasing water-stress time, the activities of SOD, POD and the contents of MDA is increased.while the activities of CAT is deceasedThe results of test in vivo and in vitro showed that exogenous Spm not only stimulated the enzyme synthesis of SOD and POD , but also promoted the activity of the existing enzyme; exogenous Spm stimulated the synthesis of CAT , but had no effect on the activity of the existing enzyme. It indicated that the ways through which Spm increases the activity of SOD , CAT and POD in alfalfa seedlings were different . The suitable density was in the scope of 0.1~lmmol/L and the best effect is the treatment of 0.1 mmol/L.The second part studied the component of seed coating formulation which could improve germination of alfalfa seeds and seedlings growth of alfalfa under water stress to increase the alfalfa Seedlings the tolerance to drought stress. The result showed:(l) ABT 30mg/kg treatment ,NAA 2.5 mg/kg treatment .rare earth elements 400 mg/kg treatment, 6-BA 2.S mg/kg treatment and TAL 0.05mg/kg treatment is suitable to germinate of alfalfa seeds.(2) The effect of the fifth group is the best, and the next is the third while the first group is the worst in germination percentage;(3) the effect of the two different seed coating formulation on the seedlings growth of alfalfa is different. Root length and stem height of the fifth group were greater than that of the sixth group and CK;(4) mixed 0.7g superaborbent, auxiliary seed coating formulation and O.Sg growth regulators together, coating lOg alfalfa seeds with the mixture is more suitable. (5)The seed coating formulation could improve the capacities of drought resistance and promote seedlings growth under water stress. The two treatment be compared with the CK, root length, stem height, fresh weight of seedling, the contents of chlorophyll, and soluble protein, the activities of the protective enzyme system increased while the contents of MDA deceased. BZYJ-1 is better than ZYJ-1. The result showed the activities of SOD and POD were obviously increased under light and middle water stress, while decreased under severe water stress. The activity of CAT is decreased while the content of MDA is increased following the stronger water stress.