| Rhizobia isolated from nodules of Alfalfa and M.suarcolcns in drought and saline field of Linze county and drought desolate mountains Tianshui city of Gansu province were studied in this research.The results showed as follows:1.The samples were cultured on YMA medium and tested by Gram dying and BTB assay. The results showed that the 17 rhizobia are all fast-growing,Gram-negative and could produce acid.2.The Rhizobia were distinguished using RAPD Molecular Marker Method.17 Rhizobia were classified as 6 strains.3.The ability of salt and alkali tolerance of the 6 strains were tested,the results showed that all of the Rizobia from Linze county had stronger tolerance ability than that from Tianshui city in several salt and pH conditions.Two strains which from Linze could grow well in pH 14 medium.another strain could grow in medium with 1.539mol/L NaCl and other two strains with 1.97 mol/L Na2SO4.Especially the strain GL007 had the strongest tolerance for salt and highest pH in YMA culture medium.GL007 is a precious strain resource of saline-alkali tolerance screening in this test.4.GL007 was inoculated into five different alfalfa cultivars by greenhouse test.The results showed that GL007 can product nodules in five alfalfa cultivars which indicated the diversity of symbiotic effect.In addition,it can promote growth of five inoculated alfalfa cultivars. After inoculation,total nodules number were increased 11.4%～77.7%,effective nodules weight were increased 26.4%～80.8%,fresh aboveground biomass weight were increased 45.8%～87.5%,dry aboveground biomass weight were increased 49.1～106.3%and crude protein were increased 1.5%～13.5%after inoculation.The fresh aboveground biomass weight,dry aboveground biomass weight and crude protein of Golden Empress was increased 82.6%,106.3%and 13.5%,respectively.which showed significantly different with CK.The effective symbiotic system which has a great potential for production practice screened in this experiment is needed to be verified in saline field in the future. |
