Screening Of Cynodon Dactylon Germplasm Of Xinjiang Under NaCl Stress

Cynodon dactylon of Poaceae is perennial root-stoloniferous herbaceous plants and had the advantage of high reproduction,drought resistance,salt resistance and trampling resistance.In Xinjiang,the environment of C.dactylon is cpmplex,there are abundant resources and phenotypic differences of C.dactylon.while up to now,the research about salt tolerance is limited on cultivating new varieties and selecting of new strains,we used the simulation of NaCl stress in this study,identified and evaluated the salt tolerance of 50 materials of C.dactylon where grew up in different habitats of Xinjiang.The results were as follows:(1)With salt concentration increasing(0,0.4%,0.8%,1.2% and 1.6%NaCl stress),the relative germination rate,relative germination energy and germination index of C.dactylon significantly decreased,the length of radical and plumule increased first then decreased,the peak was during 0.4% NaCl.With salt concentration increasing,the variation coefficient of all indexes increased and the variation coefficient under 1.6% salt stress was above 2.0 times more than that of the control.The semi-lethal NaCl concentration of C.dactylon germplasms was 1.28%,its variation coefficient was 45.66% and the optimum concentration to evaluate salt tolerance of C.dactylon was 1.2% NaCl.According to comprehensive cluster analysis of fifty Xinjiang C.dactylon,Cd012 was indived to salt-toleranct germplasm,Cd019,Cd021,Cd020 and Cd054 were moderate salt-tolerant germplasms,Cd001,Cd033,Cd035,Cd057 and Cd059 were salt-sensitive germplasms.(2)Compared with CK,under 1.5% NaCl stress(salt/soil ratio),the above ground biomass,growth speed,tiller speed,leaf water content of C.dactylon significantly decreased,the leaf firing percentage,relative electricity conductivity,chlorophyll content and carotenoin content increased significantly.Based on the mebership runction method,evaluating comprehensively salt tolerance at seedling stage of C.dactylon.Cd012,Cd032,Cd033,Cd035 were indived to salt-toleranct germplasms,Cd006,Cd007 and other 32 materrials were moderate salt-tolerant germplasms,Cd001,Cd004 and other 14 materrials were salt-sensitive germplasms.(3)The correlation analysis showed that there was no significant correlation between germination stage and seedling stage.Evaluation of germination stage and seedling stage salt tolerance of C.dactylon by principal component analysis and membership function method,the results show that the salt-toleranct germplasms contain Cd005,Cd012,Cd028,Cd032,moderate salt-tolerant germplasms contain Cd007,Cd008 and other 29 materials,salt-sensitive germplasms contain Cd015,Cd023,Cd033,Cd035,Cd036,Cd037,Cd048,Cd057,Cd059.