岩溶区与非岩溶区3种土地利用方式下土壤细菌群落结构比较

为研究岩溶区土壤微生物的特性，揭示其在岩溶土壤碳循环的作用，选取桂林毛村岩溶试验场为研究点，采集岩溶区、混合区与非岩溶区中的稻田、玉米和柑橘园表层土壤，采用高通量测序方法，对比细菌群落丰度、组成及多样性特征的异同。结果显示，在得到的48 159条序列中，共有2 602个OTUs。土壤细菌优势门（相对丰度>10%）为变形菌门（Proteobacteria）、酸杆菌门（Acidobacteria）和放线菌门（Actinobacteria）；优势纲（相对丰度>10%）为酸杆菌纲（Acidobacteria）和β-变形菌纲（β-proteobateria）。岩溶区土壤细菌门水平上的变形菌门和Latescibacteria的细菌和目水平上的酸杆菌亚群GP6的丰度均高于混合区和非岩溶区，而科水平上酸杆菌亚群GP1和目水平上的酸杆菌亚群GP2的相对丰度低于混合区和非岩溶区。冗余分析结果表明，土壤有机碳、pH和总氮等是引起细菌群落结构变化的关键因子。 

Comparison of soil bacterial community structures from three soil land-use between karst and non-karst areas under three kinds of land use

The purpose of this study is to reveal the effect of microbe on the cycle of soil organic carbon (SOC) in karst areas. Soil samples of paddy fields，maize fields and citrus orchards were collected from a karst area, mixed area and non-karst area at the Maocun karst experimental site in Guilin. The abundance, composition and diversity of microbe were compared based the results from high-throughput sequencing technology. The results show that there are 48,159 sequences with 2,602 OTUs. The dominant phylum of soil bacteria (relative abundance >10%) are Proteobacteria, Acidobacteria and Actinobacteria. The dominant classes (relative abundance >10%) are Acidobacteria and β-proteobateria. The OTUs abundances of both Proteobacteria and Latescibacteria subgroup 6 in the karst area are higher than those in the other two areas. The relative abundances of both subgroup1 and subgroup 2 in the karst area are lower than those in the other areas. Redundancy analysis indicates that SOC, pH and total nitrogen are the key factors to cause microbial changes.