Study On Comprehensive Evaluation And Mechanism Of Drought Resistance For Medicago Glutinosa

In this research,indexes of drought resistance were measured under soil drought stress,which were used to evaluate comprehensively the drought resistance of 15 accessions of Medicago glutinosa, during seedling stage in the greenhouse. According to the results,3 materials with different drought resistance were selected to study the drought resistance mechanisms. The main results of research were as following:1.13 drought resistance indexes could be classified into under ground biomass factor,growth factor,above ground biomass factor,root factor and stress index factor 5 component parts according to principal components analysis,the following indexes were related to drought resistance of Medicago glutinosa germplasm resources,such as under/above biomass , underground biomass stress index,under/above biomass stress index and so on. And made a compositor about the drought resistance of 15 accessions of Medicago glutinosa according to average of subordinate function.2.The leaves of relative electric conductivity, WSD,the content of MDA ,Pro and WSS were increased obviously with the aggravative of drought stress,the changees were related to drought resistance of Medicago glutinosa. The accumulation of Pro and WSS were different because of different materials. The drought resistance material was more than that of the weaker one,while relative electric conductivity,MDA,WSD were opposite. RWC and water potential represent descendant trend,the descendant trend of RWC was that the drought resistance material was less than that of the weaker ones,while the leaf water potential was reverse.3.The results of photosynthetic mechanism for 3 accessions of Medicago glutinosa show that the net photosynthetic rate,transpiration rate,stomatal conductance decreased rapidly,the materials ZXY06P-2636 decreased rapidly compared with the drought resistance material ZXY06P-2533.4.The results of endogenesis hormones for Medicago glutinosa showed that the content of ABA in the leaves were increased at different extent,but the range were different because of the materials. There is still growth potential for ZXY06P-2636 under drought stress,because the trend of IAA was ascend,but under severe stress the content of IAA increased largest for ZXY06P-2533,showed that the growth of potential is the largest. The content of GA3 and ZR present downtrend under water stress,showed that the plant alleviate stress to achieve normal physiological activity through slowing the growth rate because of the shortage of water. There were different adjustment mechanisms of endogenous hormone because of different materials .5. Anatomic indexes of leaves were measured for three materials,The results showed that Leaf thickness,Stockade tissue thickness, Sponge tissue thickness ,Ratio of stockade tissue/ sponge tissue and so on were different because of materials .The indexes of drought resistance materials such as Leaf thickness,Ratio of stockade tissue/ sponge tissue, CTR ,VPD were larger than that of weak one. These structures were related to the drought resistance of Medicago glutinosa.