少花蒺藜草入侵对根际土壤磷细菌群落多样性的影响

目的]入侵植物少花蒺藜草在磷元素受限的贫瘠沙质土壤中能够快速生长和种群扩张，形成单一优势群落。本文解析了少花蒺藜草在磷胁迫条件下对磷素的高效利用机制，以期为揭示其入侵机理提供理论依据。方法]设置少花蒺藜草、冰草、狗尾草和空白对照4个处理，通过高通量测序技术，从土壤解磷微生物的角度分析各处理间土壤中解磷细菌的组成差异。结果]少花蒺藜草入侵显著提高了土壤磷酸酶的活性和土壤解磷菌的群落多样性。PCA与UPGMA聚类结果表明，少花蒺藜草与狗尾草根际磷细菌物种组成相似性最大。LEfSe多级物种差异判别分析结果表明，少花蒺藜草根际显著富集且与其他处理有显著性差异的解磷菌类群为α-变形菌、链霉菌，其在少花蒺藜草对磷的吸收中可能起较为重要的作用。变形菌门、浮霉菌门和放线菌门与少花蒺藜草根际土壤中的全磷含量呈显著正相关，放线菌门与少花蒺藜草根际土速效磷含量有紧密联系。结论]少花蒺藜草通过改变入侵地根际土壤的解磷菌群落结构间接影响根际土壤的磷素环境，从而利于自身生长。

Effects of Cenchrus spinifex invasion on phosphorus bacteria community diversity in rhizosphere soil

Aim] The invasive plant Cenchrus spinifex can proliferate and expand its population in poor sandy soils with limited phosphorus, forming a single dominant community. Analyzing the efficient utilization mechanism of phosphorus by C. spinifex under phosphorus stress can provide a theoretical basis for revealing mechanism of its invasion.Method] Four treatments of C. spinifex, Agropyron cristatum, Setaria viridis, and CK (soil without plants) were established. The compositional differences of phosphorus-solubilizing bacteria in soil were analyzed from the perspective of soil phosphorus-solubilizing microorganisms using high-throughput sequencing technology.Result] The results showed that the invasion of C. spinifex significantly improved soil phosphatase activity and the community diversity of soil phosphate-solubilizing bacteria. PCA and UPGMA clustering results showed that the species composition of phosphorus-solubilizing bacteria in the rhizosphere of C. spinifex and A. cristatum was similar. The multi-level species difference discriminant analysis results showed that the phosphate-solubilizing bacteria groups were significantly enriched in the rhizosphere of C. spinifex and significantly different from other treatments were Alphaproteobacteria and Streptomyces, which may play important roles in the absorption of phosphorus by C. spinifex. Total phosphorus content in the rhizosphere soil of C. spinifex was significantly positively correlated with the presence of Proteobacteria, Planctomycetes, and Actinobacteria, and there was a close relationship between Actinobacteria and available phosphorus content in the rhizosphere soil of C. spinifex.Conclusion] C. spinifex indirectly affected the phosphorus environment of the rhizosphere soil by changing the community structure of phosphorus-solubilizing bacteria in the rhizosphere soil of the invaded soil, which is beneficial for its growth.