对甘肃中西部及宁夏南部不同生态条件下栽培和野生豆科植物根瘤菌资源进行了调查,从36属98种豆科植物根瘤样品中分离得360株根瘤菌,其中44株是从30种未报道过结瘤情况的豆科植物中分离获得。以20属22种寄主植物对大部分菌株进行了回接结瘤实验,回接结瘤率81.2%。它们与豆科寄主植物共生结瘤85%为有效根瘤。不同种根瘤固氮活性差异较大,一般比较低,小于1μmolC2H4?gFWh的占46.6%,大于10μmolC2H4?gFWh的占6.8%,最高者仅37.73μmolC2H4?gFWh。根瘤固氮活性与寄主植物生态及生长发育期有相关性。所有分离菌株均保存在中国科学院新疆生物土壤沙漠研究所微生物研究室及中国农业大学生物学院菌种室。

The nodulation and nitrogen fixation of major cultivated and wild legumes separated from98species under36genera in central western Gansu province and southern Ningxia Re-gion have been studied.Some 360strains of root nodular bacteria have been isolated from about 400samples,among them44strains were obtained from30unreported species in Allen's"The Leguminoaes"and other literatures.Most of which were tested infecting in22model species that belong to20genera as host,81.2%strains of tested rhizobia can nodulate with host plants.Above85%of those nodule samples were effective for nitrogen fixation.The result showed that the activities of nitrogen fixation in nodules of various species varied greatly and all of them were relatively low,i.e.,46.6%of them are under1μmol C 2 H 4 ?gFWh and6.8%,more than10μmolC 2 H 4 ?gFWh .The nitrognase activity was closely related to the growth period of plants.