【作者】 张慧；

【导师】 吕成群；

【作者基本信息】 广西大学 ， 生态学， 2005， 硕士

【摘要】 本工作从厚荚相思(Acacia crassicapa)和卷荚相思(Acacia cincinnata)树种根瘤上共分离、纯化获得21个根瘤菌株,从生理生化特性、生长适应性、根瘤菌接种相思苗木、中心菌株鉴定等方面对其进行了研究。 根据菌落形成时间和代时测定结果,将供试菌株初步划分为快生菌株和慢生菌株两种类型。菌株之间在菌落形态、生长速度、生理生化特性等方面存在着明显的差异。供试菌株的最佳生长温度为28℃,所有菌株在pH值5.5-7.5范围内能够生长,能耐受0.5%的NaCl,表现出较强的耐盐性;对抗生素敏感性差异很大。初步筛选出一株耐高温、耐酸、耐盐,并且对抗生素具有广谱抗性的菌株H004。 接种相思树种根瘤菌对相思树种苗木的生长和结瘤固氮有明显的促进作用。不同根瘤菌接种对相思幼苗结瘤作用有很大区别,并与最初分离的宿主之间无明显相关性。根据接种苗木根瘤的固氮酶活、单株瘤重、单株结瘤数、结瘤率等指标,试管苗接种根瘤菌试验初步筛选出H009、H008、J012、J006为具有优良结瘤固氮能力的菌株;根据接种苗木的株高、地径、生物量等指标,盆栽试验初步筛选出H006、H007菌株作为高效结瘤固氮菌株。 对筛选出的厚荚相思菌株H006和卷荚相思菌株J006进行了菌落形态、生理生化特性的测定,结合其16SrDNA全序列分析,初步鉴定H006属于根瘤菌属(Rhizobium),J006属于中慢生根瘤菌属(Mesorhizobium)根瘤菌。更多还原

【Abstract】 Physiological and biochemical characteristics, adaptations to growth environment, inoculation in test tubes and potted seedlings, and identification of the central strains of the twenty-one rhizobial strains which isolated from root nodules of Acacia crassicapa and Acacia cincinnata were studied in this paper.According to tests of colony formation days on plate and generation time determination, all strains were primary clustered into two groups: one is fast-growing rhizobium, the other is slow-growing rhizobium. The results showed that these strains varied in colony morphologies, growth rates, physiological and biochemical characteristics of rhizobia. The optimum growth temperature of these strains was at 28℃. All strains grew with initial PH from 5.5 to 7.5 and were tolerant to salt on medium containing 0.5 % NaCl. Significant differences in antibiotic susceptibility were seen among these strains. A strain named H004 was selected with good tolerance to high temperature, acid, salt and antibiotics.Acacia crassicapa seedlings inoculated with 21 rhizobial strains in test tubes and back-inoculated with 9 rhizobial strains in soil pots, respectively. The results indicated that inoculation with rhizobia significantly stimulated the growth and nitrogen fixation ability of host seedlings. In the test-tubes experiences, nitrogenase activity, mean nodule weight per seedling, mean nodule number per seedling and nodulation rate were different and have no significant correlation with original hosts. The strains named H009, H008, J012 and J006 were screened primarily as efficient symbiotic nodulation occupancy ability. In the soil-pot experiences, according to the effects of inoculation to height, diameter and total biomass of Acacia Crassicarpa seedlings, the strains named H006 and H007 were screened primarily as efficient strains.Combining morphological, biochemical and physiological characteristics with 16S rDNA sequence analysis, strain named H006 should belong to Rhizobium, and strain named J006 should belong to Mesorhizobium.更多还原