自生固氮菌的筛选及其在灭菌土壤中的生长特性

Screening of Abiogenous Azotobacter and Its Growth Characteristics in the Sterilized Soil

从土壤中筛选自生固氮菌,用无氮培养基进行分离,以凯氏定氮法测定该固氮菌的固氮能力,观察其对水稻苗期的促生长作用,并通过MPN法测定氮细菌施用于土壤后的菌体数量,考察其在土壤中的变化动态。结果表明:筛选到固氮能力较强、对水稻有明显的促进生长作用的菌株A2,在灭菌土壤中,固氮菌增长期约为20 d,对土壤氮含量有明显提高。

The aim was to isolate and screen abiogenous azotobacter from soil,and observe its growth characteristics.The nitrogen free medium was used to separate abiogenous azotobacter.The Micro-Kjeldahl method was used to determine the nitrogen-fixing ability of the abiogenous azotobacter in order to observe its growth promoting effect in rice seedling stage.The MPN method was used to detect the number of the azotobacter,and to study its dynamic changes in the soil.The results showed that the strain A2 of azotobacter was isolated and screened,which had strong Nitrogen-fixing ability and significant effect in promoting the growth of rice.The growing period of the strain was about 20 days in the sterilized soil,and soil nitrogen content was significantly increased.