辽东山区典型人工针叶林土壤细菌群落多样性特征

为揭示不同人工林树种对土壤养分和土壤微生物群落的影响,采用Illumina MiSeq高通量测序和OTU分析法比较辽东山区白石砬子自然保护区落叶松人工林(LGe)和红松人工林(PKe),以及辽宁省森林经营研究所实验林场落叶松人工林(LGd)和红松人工林(PKd)土壤细菌群落结构的差异,同时测定土壤理化性质,探讨土壤细菌群落结构、树种和土壤环境因子的相关性。研究结果表明:(1) LGe和PKe土壤全碳、全氮和碱解氮的含量无显著差异,LGd显著高于PKd。(2)从群落组成来看,该地区落叶松和红松人工林中土壤主要由34个门类群的菌群组成,优势菌群包括变形菌门、放线菌门、酸杆菌门、绿弯菌门、疣微菌门和芽单胞菌门。(3)从群落结构来看,LGe和PKe土壤细菌的多样性和丰富度指数无显著差异,PKd的多样性指数显著极高于LGd,丰富度指数无显著差异,且Metastats分析结果表明,较LGd和PKd相比,LGe和PKe在门水平和属水平上显著差异的个数较少,表现为趋同性。(4)优势细菌类群相对丰度和土壤理化性质的RDA和相关性分析表明,土壤p H、全氮、碱解氮的含量以及C/N是本区针叶林细菌群落结构的主要影响因子。综合分析表明,在保护区选择单一树种落叶松或红松造林对改善土壤养分及优化微土壤细菌群落结构无显著差异,而在实验林场选择落叶松更有利于提高土壤肥力。

Soil bacterial community structure characteristics in coniferous forests of Montane Regions of eastern Liaoning Province, China

To determine the effect of different coniferous plantations on the soil characteristics and diversity and community structure of soil microorganisms, Illumina MiSeq high-throughput sequencing and OTU analysis were used to assess the structure of the microbial community in Larix gmelinii and Pinus koraiensis forests in the Baishilazi Nature Reserve (LGe, PKe) and the experimental forest farm of Liaoning Institute of Forest Management (LGd, PKd) in the montane region of eastern Liaoning Province, China. Soil physiochemical properties were determined to analyze the relationship among bacterial community structures, forest types, and soil environmental factors. Ours results showed that (1) soil total carbon, total nitrogen, and available nitrogen contents in LGe was not significantly different from Pke, and LGd was significantly (P < 0.01) higher than PKd; (2) 34 different bacterial phyla were identified in the soil of L. olgensis and P. koraiensis forests in this area. The dominant bacterial groups were Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, Verrucomicrobia, and Gemmatimonadetes; (3) structurally, there was no significant difference in diversity and richness indexes between LGe and PKe. The diversity indexes of the soil microbes in LGd were significantly higher than that in PKd, and there was no remarkable difference in richness indexes between them. The results of the Metastats analysis showed that the number of significantly different phyla and genera between LGe and PKe were relatively few, exhibiting a converging trend, than that of LGd and PKd; (4) redundant and correlation analyses indicated that soil pH, TN, AN content, and C/N were the main factors that correlated with microbial community structure of coniferous forests in this region. We concluded that planting L. gmelinii had no significant difference in increasing soil nutrients and improving bacterial community structure with P. koraiensis in Baishilazi Nature Reserve. However, L. gmelinii was remarkably more conducive to soil nutrient accumulation than P. koraiensis in the experimental forest farm.