Through studying the high temperature and drought resistance of Rhizobium sp.of Acacia confuse in the dry-hot valley,the Rhizobium's growth rhythm under the condition of high temperature was revealed in order to provide a theoretical basis for screening out excellent Rhizobium germplasm resources.Through field investigation,the Rhizobium sp.of A.confuse were collected from dryhot valley area,then were separated and purified.The cultivation of symbiotic tumor of the purified Rhizobium stains of A.confuse and aseptic seedlings of A.confuse was conducted,some new Rhizobium stains were selected and vaccinated to YMA culture medium,then cultured with constant temperature under different temperature gradients and the colony numbers and vertical and horizontal diameters were recorded.Through artificially simulating drought conditions,the Rhizobium stains were inoculated and cultured in the PEG culture fluid with concentration gradient of 0,5％,10％,20％,30％,the OD600 values of the bacterial suspension was determined by using spectrophotometer and the corresponding curve figure was drawn out.The experimental results show that the high temperature can significantly inhibit the growth of Rhizobium colonies; the OD values of YMA-PEG solution decreased with the increase of concentration; M-08,M-10,M-11 strains are the swains type that strongly adapted to high temperature and drought; CK,M-05,M-06,M-07,M-09,M-12,M-15 moderately adapted to high temperatures and drought; M-01,M-02,M-03,M-04,M-13 and M-14 strains had weaker adaptability to high temperatures and drought.%通过对干热河谷地区台湾相思树种根瘤菌进行高温干旱等抗性研究,揭示干热河谷地区台湾相思树种根瘤菌在高温条件下生长规律,为发掘优良的根瘤菌种质资源提供理论依据.通过野外调查、采集、分离纯化采自干热河谷地区台湾相思树种的根瘤菌；经与相思树种无菌苗共生接瘤培养,将筛选出的各根瘤菌菌株接种到YMA培养基中,于不同温度下恒温培养,记录菌落数和菌落横纵径；用聚乙二醇6 000(PEG 6 000)人工模拟干旱条件在最终浓度(w/v)分别为0,5％,10％,20％,30％等5个水平的PEG培养液中接种菌株培养,用分光光度计测定该菌悬液的OD600值并绘出相应的曲线.实验结果表明高温能明显抑制根瘤菌菌落生长. YMAPEG溶液的OD值随浓度的增大而减小,菌株M-08、M-10、M-11属于高温干旱适应较强类型,菌株CK、M-05、M-06、M-07、M-09、M-12、M-15属于高温干旱适应中等类型,菌株M-01、M-02、M-03、M-04、M-13、M-14,属于高温干旱适应较弱类型.
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