Abstract: In order to investigate the relationship between the carbon and nitrogen contents of roots,stems and leaves of Artemisia frigida,a semi-shrub plant,and the bacterial communities of its rhizosphere soil and bulk soil under different stocking rates in the desert steppe,soil (rhizosphere soil and bulk soil) bacterial diversity and community composition were analyzed by using high-throughput sequencing technology,the carbon and nitrogen contents of roots,stems,and leaves were determined,and the relationships between the bacterial diversity and carbon and nitrogen contents of roots,stems and leaves were analyzed. The results showed that the carbon and nitrogen contents of roots and leaves of Artemisia frigida were significantly affected by different stocking rates,and moderate and heavy grazing limited the growth and development of Artemisia frigida. The relative abundance of bacteria at the genus level was higher in the rhizosphere soil than in the bulk soil under different stocking rates,and the Simpson's index and ACE index of bacteria were significantly different between the rhizosphere soil and bulk soil (P<0.05). Correlation was existed between carbon and nitrogen content in Artemisia frigida root,stem leaves with the relative abundance of Rubrobacter and the relative abundance of Candidatus_Nitrososphaera in soil.

Key words: Stocking rate, Bacteria, Rhizosphere soil, Bulk soil, Root,stem and leaf, Carbon and nitrogen content

摘要： 为了探究荒漠草原不同载畜率下半灌木植物冷蒿（Artemisia frigida）根、茎、叶碳氮含量与其根际、非根际土壤细菌群落结构的关系，利用高通量测序技术分析土壤（根际和非根际）细菌多样性和群落组成，测定根、茎、叶碳氮含量，分析细菌多样性与根茎叶碳氮含量的关系。结果表明：不同载畜率对冷蒿根茎叶的碳氮含量存在显著影响，中度和重度放牧会限制冷蒿的生长发育。不同载畜率下，根际土壤属水平下细菌的相对丰度均高于非根际土壤，根际与非根际土壤细菌Simpson指数、ACE指数均存在显著性差异（P<0.05）。冷蒿根茎叶碳氮含量与土壤中红色杆菌属和亚硝化球菌属的相对丰度存在相关性关系。

关键词: 载畜率, 细菌, 根际土壤, 非根际土壤, 根茎叶, 碳氮含量