Evaluation And Research On Salt Tolerance Physiology Of Medicago Sativa

12Medicago sativa materials were studied in the thesis, seed germination rate and germination index were determinated indivitilly in different concentrations NaCl (0.0.2%、0.4%、0.6%、0.8%.1.0%.1.2%) and NaHCO3(0.0.1%、0.2%、0.3%、0.35、0.4%) solution. Experiment using pot and Saline alkali soil two kinds of planting method, The main results were as follows:1. Seed germination salt tolerance evaluation according to the differences of the half lethal concentration of relative germination index, using petri dish method under NaCl and NaHCO3stress, The results showed that the salt tolerance differences achieved a extremely significant level among the various materials. But the materials degree of salt tolerance of the NaCl and NaHCO3ress had differences, the average half lethal concentration was0.7%nder NaCl stress, the average half lethal concentration was0.35%nder NaHCO3ress, it explained that the capacity of alfalfa adapt to different single salt had differences.2. Greenhouse pot experiment according to the differences of the half lethal concentration of relative emergence rate evaluation results and petri dish method to salt grading basic consistently, the basis of physiological salt tolerance results showed that with the salt concentration increased the relative conductivity and PSⅡon-photochemical quenching coefficient (NPQ) were Significantly increased (P<0.05), Other indicators in addition to the relative water content were significantly lower (P<0.05). It explained that salt stress could cause cell membrane permeability increased, the photosynthetic capacity decreased.3.12alfalfa materials the production performance in the salt content at0.47%-0.52%saline-alkali land sorted from high to low:Yl-2> Yl-1>Zhongmu NO1> Niu she bei you xuan>Yl-4>Yl-604>Yl-80> Wudi> Yangdong> Yl-601> Yl-92> Yl-602. there were significant differences in all physiological indexes among alfalfa materials in salt environment (P<0.05), indicating that the salt ability among alfalfa materials had differences.4. Three methods of determination were basically the same sort of salt resistance except individual material, But the Petri dish method measure the salt concentration was relatively higher, and field test of saline soil had a great difference.Explain method of Petri dishes can be used to distinguish the material resistance to salt, but the correct evaluation of Alfalfa salt tolerance should be in field.