几种农业土壤中氨氧化古菌和氨氧化细菌的种群数量和组成特征

项目名称： 几种农业土壤中氨氧化古菌和氨氧化细菌的种群数量和组成特征

项目编号： No.40871129

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 轻工业、手工业

项目作者： 贺纪正

作者单位： 中国科学院生态环境研究中心

项目金额： 55万元

中文摘要： 本项目对我国几个典型农业土壤中氨氧化古菌（AOA）和氨氧化细菌（AOB）的丰度、群落组成和功能活性开展了研究，探讨了二者在土壤氮素循环中的功能及其与环境因子的关系。通过三年的努力，圆满完成研究任务，取得以下重要进展：（1）发现AOA和AOB的丰度和多样性组成在来自重庆、洪湖和盘锦的3种类型的水稻土之间差异显著，而在同一类型水稻土的不同处理间无显著差异，表明AOA和AOB的组成和分布主要受土壤类型的影响；（2）发现不同土地利用方式对酸性土壤AOA和AOB的种群数量和群落结构组成都产生明显的影响，尤其是农作区和退化区与其它区域的差异明显；（3）在内蒙半干旱温带草原土壤中，长期添加不同浓度氮源促进AOB的生长，并导致其群落组成发生明显改变，而对AOA无明显影响，表明高氮条件对AOA和AOB的群落组成及功能活性影响不同；（4）运用稳定性同位素探测技术（SIP）对AOA和AOB的功能进行了研究，发现在低氮和强酸性土壤中AOA是硝化作用的主要驱动者，为AOA参与土壤硝化作用及其在酸性土壤硝化作用中的主导作用提供了重要证据。本项目发表SCI论文8篇，中文核心期刊1篇，培养研究生4名。

中文关键词： 氨氧化古菌；氨氧化细菌；硝化作用；多样性；功能活性

英文摘要： This project aimed to understand the diversity and ditribution of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in different soil systems and to identify the key environmental factors affecting the abundance and community compostion of AOA and AOB, and then to explore their functional roles in soil nitrification. The project tasks and designted aims have been accomplished through three years' efforts. The following important findings were achieved. (1) The community structure and abundance of AOA and AOB in three kinds of paddy soil (from Chongqing, Honghu and Pangjin) were different from each other. There were minor differences among the treatments of unplanted, rhizosphere and bulk of rice-planted soil samples in the same type of paddy soil, indicating that the population size and community structure of AOB and AOA in the flooded paddy soils were mainly determined by the soil types, irrespective of rice-planted or unplanted. (2) Different land utilization patterns, including restoration (forest), degradation (pasture), cropland, tea orchard and pine plantation, caused the shift of AOA community structure, which were especially obvious in the degradation and cropland plots where frequent human disturbance occurred. The abundance of AOA and AOB, also affected by different land use significantly, is lowest or below the detection limit in degradation plot. (3) The relative long-term nitrogen loading of more than 2-4 g N m?2 year?1 resulted in diversity loss of AOB in semiarid temperate grassland of Inner Mongolia. Increasing N induced an increase in AOB abundance and caused the shift of its composition. However, AOA community remained unchanged and the highest N loading at 64 g N m?2 year?1 even decreased its abundance. The study provided convincing field experiment evidence for the effect of the relative long term of 6 years N loading levels on the soil ammonia oxidizing prokaryotes in the semiarid temperate grassland soils. (4) By using stable isotope probing technique, we studied the funcational activity of AOA and AOB in a low nitrogen input soil and a strongly acid soil. Results demonstrated that 13C-labeled CO2 was incorporated into archaeal amoA genes, but no incorporation into bacterial amoA genes was observed. CO2 fixation by AOA was accompanied by significant accumulation of nitrate during incubation peroid. High level of archaeal amoA gene abundance were observed during the active nitrification, coupled with increasing intensity of denaturing gradient gel electrophoresis (DGGE)　bands of archaeal amoA gene. All these data indicated that the active nitrification are mainly driven by archaea, not bacteria in these two kinds of soil. These studies provided direct evidence that archaeal autotrophic activity is directly linked to ammonia oxidation and firstly demonstrated the more important role of AOA than AOB in strongly acidic soil. Nine papers (including 8 SCI journal papers) were published under the support of this project.

英文关键词： ammonia-oxidizing archaea; ammonia-oxidizing bacteria; nitrification; biodiversity; functional activity