金沙江干热河谷区山蚂蝗属根瘤菌抗逆性研究

Study on the Stress Resistance of Rhizobia Isolated from Desmodium in Arid Hot Valley of Jinsha River

[目的]研究金沙江于热河谷山蚂蝗属根瘤菌的抗逆性，为优良菌株的选育提供种质资源。[方法]对34株分离自金沙江干热河谷区的山蚂蝗根瘤菌进行了耐酸碱、耐盐、耐高温或低温的抗逆性试验研究。[结果]结果表明，供试菌株的耐酸碱性较强，全部供试菌株能在pH值5．0～11．0、64．7％的菌株能在pH值4．0～12．0的YMA培养基上生长；多数菌株耐盐性弱，70．6％的菌株不能在浓度1％NaCl的YMA培养基上生长，只有29．4％的菌株能耐浓度3％-5％的NaCl环境；对温度的适应范围较宽，32．4％的菌株在4℃下表现为有活力，70．6％的菌株在10℃下能生长，37℃或60℃热激处理30min后，分别有94．3％、44．1％的菌株仍有活力，有17．6％的菌株在4～60℃均能生长，表现出极强的抗低温和抗热性。[结论]筛选到抗盐、抗酸碱、抗低温和高温性能均较强的优良菌株4株：Sdr28、Sdr32、Sdr33、Sdr34。

[ Objective ] The research aimed to study the stress resistance of Rhizobia isolated from Desmodium in Arid Hot Valley of Jinsha River for selecting fine Rhizobia strains. [ Method ] 34 Rhizobia isolated from Desmodium in arid hot Valley of Jinsha River were tested on their tolerance to NaCl, pH value and temperature variation. [ Result] The results indicated that all strains could grow on the YMA medium with a pH value range of 5.0 - 11.0 and 64.7% strains could grow at a pH value range of 4.0 - 12.0 ; 70.6% strains could not tolerate NaCl stress in 1% concentration, only 29.4% strains could tolerate NaCl stress in 3% -5% concentration. 32.4 % strains could grow below 4 ℃, 70.6% strains could grow below 10 ℃, and 94.3% or 44.1% could grow after being exposed to 37 ℃ or 60 ℃ heat shock for 30 min, and 17.6% strains could grow at 4- 60 ℃. The tested strains showed high resistance to low temperature and heat. [ Conclusion] 4 strains of Sdr28, Sdr32, Sdr33 and Sdr34 showed high tolerance to salt, acid, alkali, low and high temperature.