生物多样性 ›› 2021, Vol. 29 ›› Issue (1): 53-64.DOI: 10.17520/biods.2020137

• 研究报告:微生物多样性 • 上一篇    下一篇

土壤细菌群落特征对高寒草甸退化的响应

李世雄1,2,3, 王彦龙1,2,3, 王玉琴1, 尹亚丽1,3,*()   

  1. 1.青海大学畜牧兽医科学院/青海省畜牧兽医科学院, 西宁 810016
    2.三江源区高寒草地生态教育部重点实验室, 西宁 810016
    3.青海省高寒草地适应性管理重点实验室, 西宁 810016
  • 收稿日期:2020-04-03 接受日期:2020-08-11 出版日期:2021-01-20 发布日期:2020-09-30
  • 通讯作者: 尹亚丽
  • 作者简介:*E-mail: yaliyin@163.com
  • 基金资助:
    青海省重大科技专项(2019-SF-A3-1);青海省科技项目(2019-ZJ-7070);国家自然科学基金(31560660)

Response of soil bacterial community characteristics to alpine meadow degradation

Shixiong Li1,2,3, Yanlong Wang1,2,3, Yuqin Wang1, Yali Yin1,3,*()   

  1. 1 Academy of Animal and Veterinary Science, Qinghai University/Qinghai Academy of Animal and Veterinary Science, Xining 810016
    2 Key Laboratory of Alpine Grassland Ecosystem in the Three-River-Source, Ministry of Education, Xining 810016
    3 Qinghai Provincial Key Laboratory of Adaptive Management on Alpine Grassland, Xining 810016
  • Received:2020-04-03 Accepted:2020-08-11 Online:2021-01-20 Published:2020-09-30
  • Contact: Yali Yin

摘要:

为明确高寒草甸土壤细菌物种组成及功能结构对草地环境恶化的响应规律, 本文采用高通量基因测序技术对高寒草甸未退化、轻度退化、中度退化、重度退化和极重度退化草地土壤细菌的组成、格局和功能进行了研究。结果表明: 高寒草甸土壤优势细菌为酸杆菌门、放线菌门、浮霉菌门、变形菌门和疣微菌门, 在土壤细菌中占比分别为16%‒18%、9%‒12%、12%‒14%、23%‒29%和11%‒12%。退化草地中土壤细菌物种组成明显改变, 变形菌门细菌丰度降低, 酸杆菌门和浮霉菌门丰度增加, 不同草地科水平细菌丰度差异因土层而异。草地退化对细菌Chao1指数无影响, 轻度退化提高了细菌Simpson指数, 重度退化草地土壤细菌Shannon-Wiener指数最高。Faprotax细菌功能分组以化能异养、硝化作用、亚硝酸盐氧化及硫代谢作用为主, 草地退化改变了微生物介导的碳循环、氮循环、硫循环、铁循环和锰循环。重度及极重度退化提高了细菌氨氧化功能作用, 降低了硫化物、亚硝酸盐氧化及尿素水解作用; 草地退化过程中细菌化能异养、芳香族化合物降解及反硝化作用功能等均呈先降低后升高的变化趋势, 中度退化阶段是微生物群落生态功能结构转变的拐点。高寒草甸退化改变了土壤细菌的群落及功能结构, 土壤含水量、pH、总有机碳、全氮、全钾和有效氮磷比是土壤细菌群落及功能结构变化的主要驱动因子。

关键词: 退化高寒草甸, 土壤细菌, 物种组成, 群落特征, 生态功能结构

Abstract:

Aim: This study aims to clarify the response of soil bacterial species composition, pattern, and functional structure to a range of grassland degradation in alpine meadows.
Methods: Degraded alpine meadows at five stages (including non-degraded, light-degraded, moderate-degraded, severe-degraded, and extreme-degraded) were selected in 2017 by the classification standard in the Three-River-Source. Four different plots at each degraded stages were set as replications, and the area of each plot is about 80 m2. Soil microbial characteristics were analyzed by high-throughput gene detection, and the soil physical and chemical properties were analyzed by conventional methods.
Results: Acidobacteria, Actinobacteria, Planctomycetes, Proteobacteria and Verrucomicrobia were the dominant bacteria in alpine meadow soil, accounting for 16%‒18%、9%‒12%、12%‒14%、23%‒29% and 11%‒12%of the total soil bacteria abundance, respectively. The soil bacterial species compositions changed substantially with increasing grassland degradation: Proteobacteria abundance decreased, while Acidobacteria and Planctomycetes abundance increased significantly with increasing degradation. Furthermore, the number of taxa (at the family level) differed across the diverse soil layers in degraded alpine meadows. Grassland degradation had no effect on bacterial diversity, as measured by the Chao1 index, but alpine medow that were lightly degraded increased bacterial diversity, as measured by the Simpson index. Soil bacterial diversity, as measured by the Shannon-Wiener index, was greatest in severe-degraded grasslands. The Faprotax functions were mainly composed by the processes of Chemoheterotrophy, nitrification, nitrite oxidation, and sulfur metabolism. Grassland degradation altered the carbon, nitrogen, sulfur, iron and manganese cycles, which were mediated by microorganisms. Severe and extreme degradation increased the bacterial ammonia-oxidizing function, and decreased the functions of sulfide, nitrite oxidation, and ureolysis. Across the gradient of grassland degradation, the bacteriological Chemoheterotrophy, aromatic compounds degradation, and the denitrification functions all initially decreased before subsequently increasing; moderate stages of degradation stage represented turning points of the bacterial community in terms of ecological functional structure changes.
Conclusion: Alpine meadow degradation altered the soil bacterial community and functional structures. The main driving factors for differences in soil bacterial community and functional structures were soil moisture content, pH, total organic carbon, total nitrogen, total potassium, and the ratio of available nitrogen and phosphorus.

Key words: grassland degradation, soil bacteria, species composition, diversity, community characteristics, ecological functional structures