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    植被混凝土边坡生态恢复过程土壤细菌群落特征

    Characteristics of soil bacterial communities during ecological restoration of vegetation concrete slopes

    • 摘要: 土壤微生物是生态系统重要组成部分,对维持生态系统功能至关重要,为明确植被混凝土边坡植被恢复过程中土壤细菌群落结构。基于空间替代时间方法,选取宜昌市不同恢复年限(2、6、8、21a)植被混凝土边坡土壤为研究对象,以天然林(NF)为对照,分析土壤环境因子变化,并采用高通量测序技术测定土壤细菌群落结构。1)不同恢复年限植被混凝土边坡土壤环境因子存在显著差异,各样地土壤pH在7.51~8.02之间,均呈弱碱性,随恢复年限的增加,土壤有机碳(SOC)、全氮(TN)、速效氮(AN)、速效磷(AP)、速效钾(AK)呈现先降低后升高的趋势,全磷(TP)、全钾(TK)呈现先升高后降低的趋势。2)变形菌门(26.84%)、酸杆菌门(23.41%)、放线菌门(8.57%)、绿湾菌门(6.88%)是植被混凝土边坡植被恢复过程中的优势菌门,占群落总数的60%以上。细菌群落α多样性在恢复6a和8a时处于较高水平,2a时多样性最低,主成分分析(PCoA)分析表明不同恢复年限土壤细菌群落存在显著差异(<italic>p</italic>=0.001)。3)PICRUSt2功能预测分析显示细菌群落功能共包括6个一级功能和45个二级功能,其中新陈代谢为一级核心功能。4)不同恢复年限土壤环境因子对细菌优势菌门影响差异显著,冗余分析(RDA)分析表明pH、AN和AK是影响土壤细菌群落结构的主要环境因子。本研究揭示了植被混凝土边坡生态恢复过程中土壤微生物群落的动态变化规律,为后续边坡生态修复技术优化提供了科学依据。

       

      Abstract: Background Soil microorganisms constitute essential components of terrestrial ecosystems, exerting irreplaceable roles in regulating biogeochemical cycles, enhancing soil fertility, and maintaining overall ecosystem stability and functionality. To gain a clear understanding of the structural characteristics and compositional dynamics of soil bacterial communities during the vegetation restoration process of vegetation-concrete slopes, systematic investigations are required, as such insights are critical for unraveling the ecological mechanisms underlying the restoration of these engineered slope environments.Methods This study adopted the space-for-time substitution method, taking the soil from vegetation-concrete slopes with different restoration ages (2a, 6a, 8a, and 21a) in Yichang City as the research objects, and using the soil from natural forest land (NF) as the control. Conventional analytical methods were used to determine the changes in soil environmental factors. Combined with high-throughput sequencing technology, the structure and diversity characteristics of soil bacterial communities were analyzed, and the functions of soil bacterial communities were predicted. The purpose of this study is to reveal the dynamic evolution characteristics of soil ecosystems during the restoration process of vegetation-concrete slopes. Results 1)Significant differences were observed in soil environmental factors across vegetation-concrete slopes with varying restoration periods. Soil pH values at all sampling sites ranged from 7.51 to 8.02, indicating weakly alkaline characteristics. With increasing restoration duration, soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) all exhibited an initial decrease followed by subsequent increase. Conversely, total phosphorus (TP) and total potassium (TK) demonstrated an opposite evolutionary pattern, showing an initial increase followed by decrease as the restoration period extended. 2)Proteobacteria(26.84%), Acidobacteria(23.41%), Actinobacteria(8.57%), and Chloroflexi(6.88%) were the dominant bacterial phyla during the vegetation restoration process of vegetation-concrete slopes, accounting for more than 60% of the total bacterial community. The α-diversity of the bacterial community reached relatively high levels at the 6a and 8a of restoration, with the lowest diversity observed at the 2a. Principal Coordinate Analysis (PCoA) indicated that there were significant differences in soil bacterial communities among different restoration ages ( <italic>p</italic>=0.001). 3)PICRUSt2 functional prediction analysis revealed that the bacterial community functions encompassed 6 level-1 functional categories and 45 level-2 functional subcategories, with metabolism identified as the core level-1 function.4)The effects of soil environmental factors on the dominant bacterial phyla varied significantly across different restoration ages. Redundancy Analysis (RDA) demonstrated that soil pH, available nitrogen (AN), and available potassium (AK) were the main environmental factors influencing the structure of the soil bacterial community, exerting significant regulatory effects on the composition and distribution of bacterial communities. Conclusion Using high-throughput sequencing technology and bioinformatics analysis methods, this study systematically revealed the dynamic variation patterns of soil microbial community structure, diversity, and functional characteristics during the ecological restoration process of vegetation-concrete slopes. These findings enrich the theory regarding the distribution patterns of microbial diversity in vegetation-concrete slopes, provide important theoretical basis and practical guidance for the subsequent optimization of slope ecological restoration technologies based on microbial regulation, and hold significant application value especially in key links such as microbial agent screening, substrate improvement, and vegetation configuration.

       

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