马桑根瘤内生菌纯培养物的分离、回接及其生物学特性

多次采用根瘤切片法直接从野生的马桑根瘤中分离内生菌纯培养物均未获成功；但用同样方法从温室里人工接种形成的马桑根瘤中却分离到大量纯培养物。其中273株经盆栽回接后发现有24株能侵染结瘤；少数菌株还通过半固体斜面和珍珠岩盆栽回接成功。对10株纯培养物表型特性的研究表明，它们均具有Frankia的形态和培养特征；生理类型除有A、B两型外，尚出现有一类A、B混合型，其中凡属B型菌株的均能侵染结瘤，A型则不能，两株A、B混合型中有1株能结瘤，另1株却不能；碳、氮源利用特性和其它Frankia基本相似；细胞壁组分既有Ⅲ型也有Ⅱ型；全细胞鉴别性糖大多为木糖和半乳糖，少数菌株只含有半乳糖或木糖，或含有半乳糖、木糖和阿拉伯糖。DNA中G+C mol%为65%～74%。

Isolation, Nodulation and Characterization of Nodular Endophytes of Coriaria nepalensis

actinomycete isolates were obtained from nodules that were induced in greenhouse by the crushed field nodules collected from various locations in Southwest China. 24 isolates were shown to nodulate the plants through pot experiments. Phenotypic characterization of ten isolates was studied and revealed that they were of typical morphological and cultural characteristics of Frankia. These strains were divided into physiological group A and B, as well as group A/B which was an intermediate group between the A and B strains. It was evident that strains from physiological B but A were able to nodulate the host plant. However, one of the two isolates belonging to group A/B nodulated the host. The ultilization of carbon and nitrogen source for the strains was similar to other Frankia strains. Some strains were of type cell wall, some others were of type. Whole cell sugar patterns were diverse. Besides the common nondiagnostic sugars, most strains contain xylose and galactose, some contain xylose, gala