中文摘要：

土壤酸碱度是影响根瘤菌形成及固氮的一个主要因素，在南方酸性土壤地区，苜蓿生长的主要限制因素是固氮作用降低，筛选耐酸苜蓿根瘤菌用于接种具有十分重要的生产意义。本研究以 ９份根瘤菌株为研究对象，在不同的 ｐＨ条件下培养研究其菌落直径，同时在不同的 ｐＨ条件下分别与紫花苜蓿品种接种研究其结瘤数，结果表明：ＹＮＣＹ００６菌株耐酸性最强而 ＹＮＣＹ００７菌株耐酸性最差，酸性土壤条件下 ＧＴ１３Ｒ紫花苜蓿分别与 ＹＮＣＹ００６或 ＹＮＣＹ００８接种是最佳结瘤的共生系统。

英文摘要：

Soil pH is a main factor affecting the nodule formation and nitrogen fixation. Less nitrogen fixation limited the growth of alfalfa of acid soils in the South of China. It is particularly important that we select and anti-acid nodule and inoculate it. Colony diameters of nine strains and nodule number of alfalfa inoculated by theirs were studied in different acidic conditions. The result showed that YN- CY006 strain was the strongest for acid resistant, but YNCY007 strain was the weakest. For nodula- tion, GT13R alfalfa inoculation by YNCY006 or YNCY008 strain was the best symbiosis system in the acid soil.