Study On The Diversity Of Culturable Nitrogen Cycling Bacteria From The Hippophae Rhamnoides Rhizosphere Soil

The Hippophae rhizosphere soil collected from Ganna area and Tianzhu Jinqiang River as materials,to study the population structure and the diversity of nitrogen cycling bacteria isolated from the Hippophae rhizosphere soil in eastern margin of the Tibetan plateau.The colony counting method was used to statistics the quantity of nitrogen cycling bacteria,the method of ten-fold dilution was used to isolated nitrogen cycling bacteria,combining the methods of morphologic character and physical and biochemical experiments to identify the nitrogen cycling bacteria.To analysis the quantity of nitrogen cycling bacteria isolated from the Hippophae rhizosphere soil,we know that the quantity of nitrifying bacteria is about1.67±0.44⁹.81±0.65×10⁵CFU·g^-1 in dry soil and the quantity of nitrogen-fixing bacteria is about 7.05±0.71¹6.00±0.59×10⁵CFU·g^-1 in dry soil of Hippophae thibetana rhizosphere soil in Tianzhu Jinqiang River.The quantity of nitrifying bacteria is about 0.43±0.06⁵.69±0.81×10⁵CFU·g^-1 in dry soil and the quantity of nitrogen-fixing bacteria is about 3.01±0.39⁶.23±0.69×10⁵CFU·g^-1 in dry soil of Hippophae thibetana rhizosphere soil in Gannan area.The quantity of nitrifying bacteria is about 5.54±0.34²1.19±0.61×10⁵CFU·g^-1 in dry soil,the quantity of nitrogen-fixing bacteria is about 4.09±0.61⁹.15±0.57×10⁵CFU·g^-1 in dry soil and the quantity of denitrifying bacteria is about 0.69±0.37×10⁵CFU·g^-1 in dry soil of Hippophae rhamnoides subsp.sinensis rhizosphere soil in Gannan area.This study totally isolated 220 nitrogen cycling bacteria.51 nitrifying bacteria belong to 4 Genus（Bacillus、Nitrosomonas、Nirtosogloea and Nitrosococcus）and39 nitrogen-fixing bacteria belong to 3 Genus（Azotobacter、Azomonas and Derxia）were isolated from Hippophae thibetana rhizosphere soil in Jinqiang River.32nitrogen-fixing bacteria belong to 4 Genus（Bacillus、Nitrosomonas、Nirtosogloea and Nitrosococcus）and 21 nitrogen-fixing bacteria belong to 2 Genus（Azotobacter and Azomonas）were isolated from Hippophae thibetana rhizosphere soil in Gannan area.50 nitrogen-fixing bacteria belong to 5 Genus（Bacillus、Nitrosomonas、Nirtosogloea、Nitrosococcus and Nitrosocystis）,26 nitrogen-fixing bacteria belong to 3Genus（Azotobacter、Azomonas and Derxia）and 1 denitrifying bacteria were belong to Bacillus isolated from Hippophae rhamnoides subsp.sinensis rhizosphere soil in Gannan area.The diversity of nitrogen cycling bacteria in Tianzhu Jinqiang River area of Hippophae thibetana rhizosphere soil:the quantity of nitrifying bacteria in autumn is most abundant;the diversity of nitrifying bacteria in winter is most abundant.The quantity and diversity of nitrogen-fixing bacteria in Tianzhu Jinqiang River is most abundant in winter.The diversity of nitrogen cycling bacteria in Gannan area of Hippophae thibetana rhizosphere soil:the quantity and diversity of nitrifying bacteria is highest in Gahai.The quantity and diversity of nitrogen-fixing bacteria in Gaxiu is most abundant.The diversity of nitrogen cycling bacteria in Gannan area of Hippophae rhamnoides subsp.sinensis rhizosphere soil:the quantity and diversity of nitrifying bacteria in Hezheng is most abundant.The quantity and diversity of nitrogen-fixing bacteria in Bola is most abundant.Only 1 denitrifying bacteria were isolated from Bola and belong to Bacillus.