| 摘要: |
| 为探究高寒森林凋落物分解过程中土壤微生物群落结构的变化，揭示海拔对土壤微生物群落和凋落物分解的影响，本研究于西藏色季拉山3 500~4 300 m海拔梯度开展为期一年的凋落物掩埋实验，结合微生物群落结构变化和不同海拔凋落物降解规律来分析，阐明土壤理化性质、微生物群落结构和凋落物分解的响应关系。结果表明：不同海拔土壤细菌群落组成相对稳定，优势菌门丰度受总氮、碳氮比显著影响（P<0.05）；土壤含水率、碳氮比显著影响真菌优势菌门变化（P<0.05）；细菌和真菌群落的α-多样性指数均受海拔、凋落物降解及二者交互作用的显著影响（P<0.001）。高海拔（4 100和4 300 m）和低海拔（3 500、3 700和3 900 m）土壤微生物群落结构分别具有一定相似性，而不同海拔细菌和真菌共生网络复杂程度差异较大；掩埋1年后，凋落物在不同海拔的降解率为28.2%~45.2%，碳氮比与凋落物降解率呈显著负相关关系（P<0.05）。研究发现，海拔、碳氮比、土壤含水率均对细菌、真菌群落演替和凋落物降解率产生直接或间接的影响，真菌群落较细菌群落对凋落物降解贡献更大。本研究可为色季拉山高寒森林不同海拔微生物群落结构变化和凋落物降解规律提供科学依据。 |
| 关键词: 海拔 细菌 真菌 凋落物 降解率 |
| DOI：10.11841/j.issn.1007-4333.2024.02.04 |
| 投稿时间：2023-06-23 |
| 基金项目:西藏高原森林生态教育部重点实验室开放课题（XZA-JYBSYS-2020-02）；西藏自治区科技创新基地自主研究项目（XZ2022JR0007G） |
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| Changes of soil microbial communities during litter decomposition in alpine forests at different elevations |
|
HOU Zhuonan1, ZHANG Xinjun2, WANG Ruihong2, LI Ao1, LI Xintong1, WEI Yuquan1*
|
| (1.College of Resources and Environment, China Agricultural University, Beijing 100193, China;2.Institute of Tibet Plateau Ecology/Key Laboratory of Forest Ecology in Tibet Plateau, Tibet Agricultural & Animal Husbandry University, Nyingchi 860000, China) |
| Abstract: |
| In order to explore the changes of soil microbial community structure in the process of litter decomposition in alpine forest and reveal the effects of elevation on soil microbial community and litter decomposition， this study conducted a one-year litter burial experiment at an elevation gradient of 3 500—4 300 m in Mount Segrila， Tibet， and analyzed the changes of microbial community structure and the degradation rules of litter at different elevations. The response relationship between soil physicochemical properties， microbial community structure and litter decomposition was elucidated.The results showed that the composition of soil bacterial community was relatively stable at different elevations， and the abundance of dominant bacterial phyla was significantly affected by total nitrogen and carbon nitrogen ratio （P<0.05）. Soil moisture and carbon nitrogen ratio significantly affected the changes of dominant fungi （P<0.05）. The α-diversity indices of bacterial and fungal communities were significantly affected by elevation， litter degradation and their interactions （P<0.001）. The soil microbial community structure at high elevation （4 100 and 4 300 m） and low elevation （3 500， 3 700 and 3 900 m） was similar， but the complexity of bacterial and fungal symbiotic network at different elevations was significantly different. After one year of burial， the degradation rate of litters at different elevations ranged from 28.2% to 45.2%， and there was a significant negative correlation between carbon nitrogen ratio and degradation rate of litters （P<0.05）. In conclusion， the elevation， carbon nitrogen ratio and soil moisture all had direct or indirect effects on the succession of bacterial and fungal communities and the degradation rate of litters， and the fungal community contributed more to the degradation of litters than the bacterial community. This study can provide scientific basis for the changes of microbial community structure and litter degradation at different elevations in the alpine forest of Mount Segrila. |
| Key words: elevation bacteria fungi litter degradation rate |
