Abstract: An experiment was conducted to examine the impact of shade stress on soil microbial community structure and diversity in the rhizosphere of shade-tolerant Ophiopogon japonicus (Linn. f.) Ker-Gawl. (OJ) and shade-intolerant perennial turf-type ryegrasss (Lolium perenne L.,LP). Bacterial community structure was assayed using high-throughput sequencing platform,targeting the 16S rRNA gene. The results showed that shade stress changed the contents of NH₄⁺-N and NO₃^--N,total P,total K,available K,and available P in the rhizosphere soil of OJ and LP. Shade stress significantly changed the composition of bacterial communities,while had little impact on the diversity of the OJ and LP's microbial communities. The bacterial communities were mostly composed of Proteobacteria and Acidobacteria in the rhizosphere soil of OJ and LP. The relative abundances of Proteobacteria and Acidobacteria in the rhizosphere soil of OJ and LP were 26.34%~35.23%,19.79%~24.24% and 19.03%~24.49%,19.20%~32.96%,respectively. The relative abundances of Chloroflexi and Verrucomicrobia decreased in OJ soil in response to shade stress,and higher abundances was observed in LP soil compared to OJ soil. The correlation analysis indicated that available K and total N were major factors affecting the bacterial assemblages in the rhizosphere soil of OJ,while total N,NH₄⁺-N and NO₃^--N concentration had strong effect on bacterial assemblages in the rhizosphere soil of LP. In conclusion,shade stress changed the soil physicochemical properties and bacterial community structures;plants per se have stronger impacts on soil bacterial community than shade stress.

Key words: Shade stress, Rhizosphere soil bacteria, Ophiopogon japonicus (Linn. f.) Ker-Gawl., Lolium perenne L.

摘要： 为探究麦冬（Ophiopogon japonicus（Linn.f.）Ker-Gawl.，缩写为OJ）和多年生黑麦草（Lolium perenne L.，缩写为LP）根际土壤微生物群落对遮阴胁迫的响应机制，本试验利用Illumina HiSeq2500测序平台，以16S rRNA基因为标靶进行相关研究。结果表明：遮阴改变OJ和LP土壤中硝态氮、铵态氮、全磷、全钾、速效钾和速效磷含量；遮阴显著改变OJ和LP根际土壤细菌群落组成，但是对其多样性影响不显著；OJ和LP根际土壤中变形菌门（Proteobacteria）和酸杆菌门（Acidobacteria）为主要优势菌群，相对丰度分别为26.34%~35.23%，19.79%~24.24%和19.03%~24.49%，19.20%~32.96%。遮阴导致OJ根际土壤中变形菌门、绿弯菌门（Chloroflexi）和疣微菌门（Verrucomicrobia）的丰度降低，而LP根际土壤中其相对丰度显著高于OJ。相关性分析表明：土壤速效钾、全氮是影响OJ根际土壤细菌群落结构的主要原因，而铵态氮、硝态氮、全氮是影响LP根际土壤细菌群落结构的主要原因。因此可得出，遮阴改变了OJ和LP土壤的理化性质，改变了其根际土壤中优势细菌类群组成，而植物本身对土壤细菌群落组成的影响强于遮阴胁迫。

关键词: 遮阴胁迫, 根际土壤微生物, 麦冬, 多年生黑麦草