Abstract: The quantity, antibacterial activity and species composition of moderatelyhalophilic actinomycetes isolated from the Nam Co Lake, a salt lake in Tibet, were researched. The samples collected from the Nam Co Lake were isolated with 4 isolation media containing 5% and 10% NaCl by dilution plate pouring process. Based on morphological characters, culture characters and cell-wall chemical composition, the strains were preliminarily identified, and the bacteriostasis and enzymatic activity of the isolated actinomycetes were tested. The results show that 36 strains of moderately-halophilic actinomycetes were isolated, in which 26 strains were isolated from soil samples and 10 from water samples. They were identified as Streptomyces, Nocardia, Nocardiopsis and Rhodococcus.The trains were merged into 13 trains based on the morphological characters of the actinomycetes. The results of antibacterial activity experiment showed that there were 4 strains of actinomyces to have a bacteriostatic activity to Fusarium graminearum, Bipolaris sorokinianum and Alternaria alternata, and the antibacterial rate accounted for 30.8%.The restriction activity was the highest to Bipolaris sorokinianum, and the largest antibacterial circle diameter was up to 22 mm.

Key words: font-family: 宋体, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, moderatelymso-bidi-language: AR-SA">moderatelyfont-family: 宋体, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, -halophilic actinomycete')">mso-bidi-language: AR-SA">-halophilic actinomycete, population, bacteriostatic activity, enzymatic activity, Nam Co Salt Lake