银合欢根瘤菌的生理生化特性及共生固氮效应

PHYSIOLOGICAL CHARACTERISICS AND SYMBIOTIC N2-FIXATlON EFFICIENCY OF RHIZOSIA ISOLATED FROM LEUCAENA LEUCOCEPHALA

所试的七个菌株都是快生型根瘤菌.能利用包括双糖在内的较多的碳水化合物,对多数碳源基质,在利用的同时产酸.除菌株CB81外,其他菌株的代时在3.5小时以下,而菌株CB81的代时为7.2小时.这些菌株能利用无机和有机态氮,但蛋白胨和酵母提取物是良好的氮源.它们在氧化酶、接触酶、脲酶和硝酸还原酶试验中皆呈阳性;在石蕊牛奶试验中产血清环;大多数菌株在pH4.0-9.0仍能生长;这些菌株的耐盐性不超过0.2M NaCl,结瘤实验证明本地菌株LL2的共生固氮能力超过国外菌株TAL1145和CB81.

Seven strains tested are fast growers. They utilize a variety of carbohydrates including disaccharides and produce acid with most of these carbon sources. Their generation time, except strain CB81, is less than 3.5 hours, but the generation time of strain CB81 is 7.2 hours. These strains can utilize organic and inorganic forms of nitrogen, but peptone and yeast extract are suitable nitrogen sources. All the strains are oxidase, catalase, urease, nitrate redutase positive and produce serum zones in litmus milk ' The toleration of these strains to Nad is less than 0.2M. Most of them are capable of growth at pH 4.0-9.0. Laboratory examination showed that the nitrogen fixation ability of native strain LL2 is better than that of strains TAL1145 and CB81.