荒漠灌木内生固氮菌对环境因子的适应性研究

 以塔里木河下游荒漠灌木多枝柽柳(Tamarix ramosissima Ledeb.)、黑果枸杞(Lycium ruthenicum Murr.)组织中分离获得的5个内生固氮菌株为材料,研究了pH值、温度、含盐量、化合态氮含量、干旱对其生长和固氮能力的影响。结果表明,测定菌株对酸碱、温度适应范围广,在pH值5.0～10.0和15～40 ℃温度范围内均能生长并表达固氮酶活性; 菌株能耐受0.1%～5.0%NaCl、0.5～4 mmol·L-1NH+4、-0.3～-0.15 mPa渗透势,表现出较强的抗逆性能,但各菌株之间存在一定差异。

Adaptability of Endophytic Diazotrophic Bacteria Strains from Desert Shrubs to Diverse Environment Factors

In this study, five endophytic diazotrophic bacteria strains isolated from Tamarix ramosissima Ledeb. and Lycium ruthenicum Murr. at the lower reaches of the Tarim River in Xinjiang were examined for their adaptability to the stress of pH, temperature, NaCl, NH+4 and drought. The results showed that all the strains could grow and exhibit nitrogenase activity under wide range of temperature of 15—40 ℃ and pH from 5.0—10.0. The strains could also tolerate sodium chloride concentrations of 0.1%—5.0%, NH++ concentrations of 0.5—4.0 mmol·L-1 and osmotic potential of －0.3—－0.15 mPa, respectively. It was suggested that the strains had superior tolerance to stress of diverse environment factors, but their tolerance abilities differed partly.