Evaluation And Research On Drought Tolerance Physiology Of Seedling Medicago Sativa

Evaluation studies of drought resistance on 133 were from home and abroad different alfalfa.According its symptoms of drought response and survival after re-water comprehensive analysis and will be divided into five different drought resistance levels ,which methods of seedling drought are continuous and repeatedly. Select 10 typical materials from different drought tolerance grade and research the drought tolerance physiological differences in alfalfa adult and seedling stage.The results are as follows:1. The two evaluations of 133 alfalfa materials in seedling period results showed: reach significant or very significant different between materials. Whole analyze showed that most of the domestic varieties show strong drought resistance than foreign varieties and new strain bred widespread better than previously resistant varieties bred.2. The results of compared with germination index and drought resistance of 133 materials showed that the relationship of seedling survival after re-watering and germination index of two evaluation of drought both are negative correlation, moreover the results of 2008 year reach a significant level (P<0.01) and the results of 2009 year reach a significant level (P<0.05).3. Select different levels of drought tolerance 10 typical materials and research of physiological in seedling an adult. The results of physiological parameters show: proline (F=-0.933**), POD (F=-0.952**), SOD (F= -0.869**) increase rate of three physiological indicators and evaluation rank of drought tolerance correlation analysis showed significant negative correlation, membrane permeability (conductivity) (F = 0.938 **) showed significant positive correlation correlation.According increase rate of proline ,POD,SOD three index and membrane injury rate analysis the sensitive order of four indicators is: free proline >membrane increase rate > SOD > POD. Above results suggest that: the mainly physiological basis of drought tolerance of alfalfa is accumulation of proline, increased activity of defense enzyme and reduce Membrane permeability.