| 黑河上游不同植被类型土壤细菌群落多样性、功能及季节动态 |
| 摘要点击 1244 全文点击 381 投稿时间：2022-10-28 修订日期：2023-01-14 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 土壤细菌群落 功能预测 植被类型 季节差异 黑河上游 |
| 英文关键词 soil bacterial community function prediction vegetation types seasonal dynamics the upper reaches of the Heihe River |
|
| 中文摘要 |
| 土壤微生物群落与植物群落间的作用机制是探究生物地球化学循环过程和维持植被生态系统稳定的关键.黑河上游植被的垂直分布特征明显，选取垫状植被（CV）、灌丛草甸（HM）、森林草原（FS）、山地干草原（MS）和荒漠草原（DG）共5种典型植被样地，运用高通量测序技术分析冬、夏季不同植被类型土壤细菌的群落结构和多样性，基于FAPROTAX数据库进行群落功能预测，运用冗余分析、结构方程模型探讨驱动土壤细菌群落的主要环境因子，并揭示细菌群落变化的作用机制与季节差异.结果表明：①不同植被类型和季节下土壤理化性质差异显著，各指标随土壤深度的变化规律不同，森林草原（FS）的土壤含水率和碳氮养分含量更高；②细菌群落α-多样性指数在季节间的差异（P<0.05）大于植被类型（P>0.05），冬季群落丰度整体高于夏季，物种多样性在冬季随海拔呈"倒U "型分布，夏季呈" W"型分布；③细菌群落结构和组成在门水平上无显著差异，优势种群为酸杆菌门（Acidobacteria）、变形菌门（Proteobacteria）和放线菌门（Actinobacteria），但在属水平上随季节有明显不同；④土壤细菌群落的功能随植被类型和季节变化较小，均以化能异养、硝化和氨氧化作用为主；⑤影响细菌群落的关键因子存在季节差异，冬季为土壤温度（ST）、总有机碳（TOC）和pH，夏季为土壤含水率（SWC）、碳氮比（C/N）和pH；⑥土壤细菌群落受彼此关联的环境因子的协同作用，土壤理化性质对细菌群落多样性和功能的影响较植被类型更直接，改善土壤的碳、氮水平有助于提升细菌的物种和功能多样性.研究结果可为探索区域植被退化机制和维持高寒生态系统稳定提供参考. |
| 英文摘要 |
| The process of interaction between the plant and soil microbial communities holds the key to understanding the biogeochemical cycle and preserving the stability of vegetation ecosystems. Owing to this significance, the primary goal of this research was to give a starting point and reference methods to restore local vegetation. The vegetation distribution in the mountainous area of the upper reaches of the Heihe River Basin had notable vertical zonality, which was characterized by five typical vegetation types, including cushion vegetation(CV), herbage meadow(HM), forest steppe(FS), mountainous steppe(MS), and desert grassland(DG). The organization and diversity of soil bacterial communities in various vegetation types were examined using high-throughput sequencing techniques in both the winter and summer seasons. Sampling sites were chosen in each of the five common vegetation types in turn. Additionally, based on the FAPROTAX database, the predicted functions of microbial communities were evaluated for different vegetation types and seasons. The redundancy analysis and structural equation model were also used to investigate the primary environmental elements and uncover the mechanisms affecting the soil bacterial populations. The findings revealed that:① the physical and chemical properties of soil differed significantly among vegetation types and seasons, and the property indices varied dissimilarly with depth. In particular, the soil water content(SWC) and nutrient content of total organic carbon(TOC) and total nitrogen(TN) were significantly higher in forest grassland(FS). ② The divergences of α-diversity indices among seasons(P<0.05) were greater than that of vegetation types(P>0.05). The Chao1 index measuring the abundance of the bacterial community was higher in winter. According to the Shannon index, the species of the bacterial community were dispersed in a "W" shape in the summer and a "hump" form in the winter with altitude. ③ The predominant phyla of the bacterial community, composed of Acidobacteria, Proteobacteria, and Actinobacteria, did not significantly differ from one another. However, the organization of the bacterial community presented a significant variation seasonally at the genus level. ④ The primary functions of the soil bacterial population, which largely consisted of chemoheterotrophy, nitrification, and aerobic ammonia oxidation, were not significantly different among vegetation types and seasons. ⑤ The key factors affecting soil bacterial communities at the genus level varied significantly among seasons, with soil temperature(ST), total organic carbon(TOC), and pH in winter and soil water content(SWC), carbon-nitrogen ratio(C/N), and pH in summer. ⑥ Synergized by interrelated environmental factors, soil physical and chemical features exerted a more direct impact on the diversity and functionality of bacterial communities compared with vegetation types, including significantly changing the abundance of Acidobacteria and Bacteroidetes, as well as the role of nitrification and ammonia oxidation. Hence, improving the carbon and nitrogen contents in soil nutrients would help to enhance the diversity and function of bacterial communities. The findings of this study provided a model for determining the mechanism of regional vegetation degradation and preserving the stability of alpine ecosystems in this area by revealing the seasonal distribution pattern of bacterial communities and the key biological processes beneath the typical vertical vegetation band in the upper reaches of the Heihe River. |
|
|
|
