马占相思根瘤菌生物学特性的研究

Biological Characteristics of Rhizobia in Acacia mangium

为了探讨马占相思根瘤菌的生物学特性,从广西高峰林场马占相思林分采集分离到9株根瘤菌,并对其生理生化特性、抗逆性和固N酶活性进行研究。结果表明,大部分菌株能较好利用供试糖源,所有供试菌株在3-酮基乳糖反应、牛肉膏蛋白胨、明胶水解、淀粉水解试验中呈阴性;在B.T.B反应、无机N源利用、柠檬酸盐利用呈阳性,硝酸盐还原试验大多呈阳性;石蕊牛奶试验除M Z02、M Z04产酸外,其余菌株产碱。所有供试菌株在温度30℃时生长最好,耐盐、耐酸碱范围较宽,M Z04在含盐浓度为2.0%环境还能生长良好,M Z04、M Z10在pH 9.0环境仍能生长较好;所有菌株对250μg/mL庆大霉素(Sm 3)均无抗性,不同菌株对其余供试抗菌素表现出不同的抗性,M Z02抗性最差,对所供试的抗生素均无抗性;M Z04、M Z08、M Z09抗性相对较强。所有供试菌株都具有固N酶活性,其中M Z02、M Z06、M Z08的固N酶活性最高。根据广西马占相思栽培区的生态条件,筛选出M Z02和M Z06为优良菌株。

To study the biological characteristics of Rhizobia in Acacia mangium, 9 rhizobia strains were isolated from A. mangium in Gaofeng forest farm of Guangxi, and the physiological and biochemical characteristics, resistances and nitrogenase activities were detected, respectively. The results showed that sugar sources could be well used by most strains. In the experiments treated with 3-keto-lactose, beef-protein, gelatin hydrolysis and starch hydrolysis, all of testied strains were negative, In B. T. B reaction, inorganic nitrogen sources utilization and citrate utilization, the results were positive. Nitrate reduction experiment presented positive largely. In litmus milk experiment, all of strains produced alkai expect for MZ02 and MZ04 produced acid reactions. At 30C, all of strains grew best, and had a wide range in salt, acid and basic resistance. MZ04 was capable of good growth at salt density of 2. 0%, MZ04 and MZ10 could still grew better at pH 9.0, All of the strains were not resistant to 250μg/mL gentamicin（Sm3）, and to other antibiotics, different resistances were presented by different strains, MZ02 had worst resistance to all antibiotics, while MZ04, MZ08,MZ09 had strong resistance. All strains had nitrogenase activity, of which MZ02,MZ06 and MZ08 had higher nitrogenase activity. MZ02 and MZ06 were selected as fine strains according to the ecological conditions of cultural area of A. mangium in Guangxi.