Archaea and bacteria respectively dominate nitrification in lightly and heavily grazed soil in a grassland system
Archaea and bacteria respectively dominate nitrification in lightly and heavily grazed soil in a grassland system
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DOI：
10.1007/s00374-017-1236-7
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发表时间：
2018-01-01
影响因子：
6.5
通讯作者：
Li, Yong
中科院分区：
文献类型：
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作者：
Pan, Hong;Xie, Kexin;Li, Yong
为探讨放牧率对典型草原放牧系统硝化活性和活性硝化菌群的影响，采用10年生绵羊梯度放牧试验的土壤进行了室内培养研究。采用基于DNA的稳定同位素探针（DNA-SIP）、实时定量PCR和高通量测序等分子生物学方法，研究了不同放牧率（0（SR 0）、3（SR 3）、6（SR 6）和9（SR9）只绵羊/ha）下草地硝化活性和活性硝化菌群的变化。轻度放牧（SR 3）显著提高了土壤硝化活性，而重度放牧（SR9）则显著降低了土壤硝化活性。在SR 3土壤中，亚硝化球菌（Nitrososphaera viennensis）在硝化作用中的功能优势大于氨氧化细菌（ANOB），而氨氧化细菌（ANOB）的亚硝化螺菌（Nitrosospira cluster 3）在SR9土壤中的硝化作用占主导地位。因此，载畜率改变了活性硝化群落的分布，影响土壤的化学和物理条件。
To investigate the effects of stocking rates on nitrification activity and active nitrifying communities in a typical steppe grazing system, we conducted a laboratory incubation study using soil from a 10-year-old grassland gradient grazing experiment with sheep. A combination of molecular methods, such as DNA-based stable-isotope probing (DNA-SIP), real-time quantitative PCR, and high-throughput sequencing, was used to identify changes of nitrification activity and active nitrifying communities under different stocking rates (0 (SR0), 3 (SR3), 6 (SR6), and 9 (SR9) sheep per ha). The nitrification activity of soils was significantly increased by light grazing (SR3), while it was significantly decreased by heavy grazing (SR9). Nitrososphaera viennensis lineage of ammonia-oxidizing archaea (AOA) functionally predominated over ammonia-oxidizing bacteria (AOB) in nitrification in the SR3 soil, while the Nitrosospira cluster 3 of AOB was the major player in the SR9 soil. Therefore, stocking rates altered the distribution of active nitrifying communities by affecting soil chemical and physical conditions.