苜蓿种子内生根瘤菌抗逆能力评价与筛选

Evaluation and Screening on the Stress Tolerance of Endogenous Rhizobia of Different Alfalfa Seeds

研究苜蓿（MedicagosativaL．）种子内分离的22株根瘤菌的分泌酸、抗盐性、pH值及高低温的耐受性。结果表明：22株均具有典型的根瘤菌生理生化特性，且都能分泌酸；耐盐性（10％）较强的菌株有9株，占供试菌株的40％；供试菌株耐pH值范围较广，大都在pH=5～11之间，其中耐酸性（pH=4）的菌株有6株，耐碱性（pH=12）的菌株有14株；耐高低温（40℃和4℃）的菌株有7株；综合耐盐、酸、碱、高温和低温等抗性较强的菌株有6株，分别为SM06、SA07、SA08、SX10、SD19和SL20。

The characters of acid secretion, salt resistance, pH value, and high or low temperature tolerance of 22 strains were tested. The results show that all strains can excrete acid, and about 40% of the total （9 strains） can grow in a medium containing 10% NaCl, while many of them can grow in media with pH 5-11. Six strains can survive in a medium with pH 4, and 14 strains in a medium with pH 12. Seven strains can tolerate a high temperature of 40℃ or a low temperature of 4℃. Altogether, 6 strains： SM06, SA07, SA08, SX10, SD19, and SL20 show high salt, acid, and alkali resistance, low or high temperature tolerance according to the above results.