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草业学报 ›› 2020, Vol. 29 ›› Issue (12): 161-170.DOI: 10.11686/cyxb2020109

• 研究论文 • 上一篇    下一篇

氮添加对不同坡度退化高寒草甸土壤细菌多样性的影响

李成一1(), 李希来1,2,3(), 杨元武1, 李宏林2, 梁德飞2   

  1. 1.青海大学农牧学院,青海 西宁 810016
    2.青海大学省部共建三江源生态与高原农牧业国家重点实验室,青海 西宁 810016
    3.青海 -广东自然资源监测与评价联合实验室,青海 西宁 810016
  • 收稿日期:2020-03-12 修回日期:2020-07-06 出版日期:2020-12-28 发布日期:2020-12-28
  • 通讯作者: 李希来
  • 作者简介:Corresponding author. E-mail: xilai-li@163.com
    李成一(1995-),男,青海平安人,在读硕士。E-mail: 1527523489@qq.com
  • 基金资助:
    青海省科技厅项目(2017-HZ-802);2017年度青海三江源生态保护和建设二期工程科研和推广(2017-S-1-01);高等学校学科创新引智计划资助(D18013┫项目);青海省科技计划(2020-ZJ-785);青海省科技厅自然科学基金(2018-ZJ-929Q);青海省科技厅自然科学基金(2018-ZJ-969Q)

Effect of nitrogen addition on soil bacterial diversity in alpine degraded grasslands of differing slope

Cheng-yi LI1(), Xi-lai LI1,2,3(), Yuan-wu YANG1, Hong-lin LI2, De-fei LIANG2   

  1. 1.College of Agriculture and Animal Husbandry,Qinghai University,Xining 810016,China
    2.State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University,Xining 810016,China
    3.Qinghai -Guangdong Joint Laboratory of Natural Resources Monitoring and Evaluation,Qinghai University,Xining 810016,China
  • Received:2020-03-12 Revised:2020-07-06 Online:2020-12-28 Published:2020-12-28
  • Contact: Xi-lai LI

摘要:

选取三江源区果洛州不同坡度退化程度相近的高寒草甸,进行氮添加试验,运用Miseq PE250测序技术对土壤细菌16s rDNA进行序列测定和分析,探讨3个氮添加水平低等量氮添加(LN, 2 g N·m-2)、中等量氮添加(MN, 5 g N·m-2)、高等量氮添加(HN, 10 g N·m-2)对不同坡度退化草地土壤细菌多样性的影响。结果表明:放线菌门(Actinobacteria)、变形菌门(Proteobacteria)是研究区草地土壤中最主要的两大类群。缓坡地与陡坡地土壤细菌个别丰度极低的门以及61.4%以上(包括未鉴定的细菌属)细菌属存在显著差异(P<0.05)。不同施氮水平对退化高寒草地各细菌门以及大部分细菌属影响不显著,对一些丰度较低的属的影响显著(P<0.05),且在不同坡度所响应的细菌属不同。无论是缓坡地还是陡坡地,氮添加对退化高寒草甸土壤细菌群落结构存在显著差异(P<0.05),土壤微生物丰富度和多样性整体上呈现出随着施氮量增加先减少后增加的趋势,中等量氮添加显著降低了土壤细菌丰富度和多样性,高水平氮添加显著抑制了土壤细菌的丰富度和多样性的下降(P<0.05),说明氮添加对细菌多样性的影响具有阈值限制性。

关键词: 草地退化, 外源氮输入, 细菌多样性, 高通量测序

Abstract:

The aim of this study was to determine the effects of nitrogen addition on the bacterial community in soils in degraded alpine meadows with different slopes in Guoluo Prefecture, in the Sanjiangyuan Region. Degraded grasslands with different slopes were supplemented with nitrogen at three levels: low nitrogen (LN, 2 g N·m-2), medium nitrogen (MN, 5 g N·m-2), high nitrogen (HN, 10 g N·m-2), and the effects on soil bacterial diversity were determined. The 16s rDNA region of soil bacteria was sequenced and analyzed using Miseq PE250 sequencing technology. Actinomycota and Proteobacteria were the two main bacterial classes in the grassland soil in the study area. Individual phyla with extremely low abundance in soil and those with high abundance (>61.4%), including unidentified bacterial genera, differed significantly between gentle slope and steep slope regions (P<0.05). Different nitrogen addition levels did not significantly effect on the relative abundance of bacterial phyla and most bacterial genera in degraded alpine grassland, but had significant effects on some less abundant genera (P<0.05). On both gentle and steep slopes, the overall soil microbial richness and diversity tended to initially decrease and then increase with increasing nitrogen addition. The HN treatment inhibited the decrease of soil bacterial richness and diversity. The effect of nitrogen addition on bacterial diversity was threshold-limited. Among the three treatments, the MN treatment significantly reduced soil bacterial richness and diversity (P<0.05).

Key words: grassland degradation, nitrogen addition, bacterial diversity, high-throughput sequencing