高寒草地土壤优势细菌在草地物质循环中的作用初探

选择从高寒草地土壤中分离获得的具有代表性的8株优势细菌和特有细菌菌株NX2（Acinetobacter sp．）、NX4（Arthrobacter sp．）、NX6（Chryseobacterium sp．）、NXIO（Pseudomonas sp．）、NXll（Flavobacterium sp．）、HX1（Lysobacter sp．）、WX15（Brevundimonas sp．）和HX5（Pseudoxanthomonas sp．），测定了其运动特性、生长温度和对多种碳源、氮源及对大分子物质的分解能力。结果表明：NX2、NX4、NX10和WX15具有较强的运动性；HX1和NX2在5℃下生长良好，NX4、NX6、NXIO、NX11、WX15和HX5在0℃低温下生长良好，表现出对低温很强的适应性；8种细菌对硝酸盐等无机氮、蛋白质等有机氮以及各种碳源的利用能力和利用程度均存在差异，表明细菌对草地土壤中动、植物残体的分解和利用具有一定的选择性，同时反应出这些优势细菌在物质循环和分解利用中互相分工和合作。

Preliminary study on the action of dominant bacteria from alpine grassland soil in the substance cycling of alpine grassland soil substance

Eight dominant and special bacteria isolated from the soil of alpine grassland were selected for estimating their motility,adaptability to the temperature and using ability of various carbon resources and nitrogen resources as well as decomposition of large molecular substances.The results obtained as follows:bacteria NX2,NX4,NX10 and WX15 have strong motility;HX1 and NX2 can grow well at 5 ℃,NX4,NX6,NX10,NX11,WX15 and HX5 can tolerate low temperature about 0 ℃,which show their good adaptability to alpine climate;There are discrepancy in the using ability and degree of inorganic or organic nitrogen,such as nitrate and protein,as well as various carbon resources,which tells us those bacteria not only have certain selectivity in the decomposition and utilization of animal and plant debris and leavings in the grassland soil,but also play different roles and collaborate with each other in the process of the cycling and decomposition of subtances.