| 宁夏东部荒漠草原不同密度灌丛引入过程细菌群落结构和功能特征 |
| 摘要点击 210 全文点击 12 投稿时间：2024-04-16 修订日期：2024-07-17 |
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| 中文关键词 荒漠草原 放牧退化 灌丛引入 细菌群落 网络结构 FAPROTAX |
| 英文关键词 desert steppe grazing degradation shrub introduction bacterial communities network structure FAPROTAX |
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| 中文摘要 |
| 20世纪七八十年代,为防止宁夏东部荒漠草原过度放牧引起的草原退化,大量豆科灌丛柠条（Caragana korshinskii）被引入用于植被重建,随着时间和密度的增加,出现了明显的土壤旱化,草本退化等现象.为探究“荒漠草原退化-灌丛引入”过程对土壤细菌群落及其对土壤碳氮转化的影响特征,选取封育草地、放牧草地和不同种植间距（40、6和2 m）灌丛地为研究对象,采用Illumina MiSeq高通量测序技术,开展土壤细菌差异菌群、物种网络结构和功能群及其土壤影响因子研究.结果表明,与封育草地相比,放牧草地和灌丛地增加了Firmicute、Bacteroidota和Nitrospirota的相对丰度.灌丛密度的增加促进Firmicute的相对丰度.相较于封育草地和退化草地,灌丛地细菌碳功能群明显增加碳化合物的降解,且其氮功能群随灌丛密度的增加促进了土壤氮的可利用性.灌丛引入降低了细菌优势群落和功能群与土壤因子的关联性,具体表现为在退化过程被土壤有机碳含量和β-1,4-N-乙酰葡糖苷酶调控,而在引入过程则被硝态氮和β-1,4-N-乙酰葡糖苷酶驱动,潜在加快了土壤微生物碳氮代谢过程. |
| 英文摘要 |
| In the 1970s and 1980s, to prevent grassland degradation caused by overgrazing of desert grassland in eastern Ningxia, a large number of a leguminous shrub （Caragana korshinskii） were introduced for revegetation. Over time, and with increasing density, noticeable soil aridification and herbaceous degradation occurred. To explore the effects of “desert grassland degradation-shrub introduction” on soil bacterial communities and their roles in soil carbon and nitrogen transformations, we selected enclosed grassland, grazed grassland, and shrublands with different planting spacings （40, 6, and 2 m） as the research objects. Illumina MiSeq high-throughput sequencing technology was employed to investigate differential bacterial communities, species network structures, functional groups, and their relationships with soil factors. The results showed that the relative abundance of Firmicute, Bacteroidota, and Nitrospirota increased in grazed grassland and shrubland compared to that in enclosed grassland. The increase in shrub density promoted the relative abundance of Firmicute. The bacterial carbon functional group of shrubland significantly increased the degradation of carbon compounds, and its nitrogen functional group promoted the availability of soil nitrogen with increasing shrub density compared to that of enclosed and grazed grassland. Shrub introduction reduced the association of bacterial dominant communities and functional groups with soil factors. This was evidenced by regulation through soil organic carbon content and β-1,4-N-acetylglucosidase during degradation and driven by nitrate nitrogen and β-1,4-N-acetylglucosidase during introduction, potentially accelerating soil microbial carbon and nitrogen metabolic processes. |
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