[Objective] The aim of the present study was to investigate the bacterial structure and diversity of rhizosphere soil of different plantations and their influencing factors in Yellow River Delta.[Method] Based on the high throughput sequencing technology,this research compared the rhizosphere soil bacterial community structure and diversity of Ailanthus altissima,Ulmus pumila,Fraxinus velutina,Robinia pseudoacacia,and analysed correlation with soil properties.[Result] The results of high throughput sequencing showed that there were 27,26,28,and 28 phylum bacteria in the rhizosphere soil of A.altissima,U.pumila,F.velutina,and R.pseudoacacia.Acidobacteria,Proteobacteria,and Actinobacteria were dominant bacteria taxa with their relative abundance more than 10％,and Nitrospirae,Chloroflexi,Planctomycetes,Gemmatimonadetes,and Verrucomicrobia were main bacteria taxa with their relative abundance more than 1％.There was significant difference in the relative abundance of Proteobacteria,WS3,Cyanobacteria,Euryarchaeota,Firmicutes,OD1,and Tenericutes in the rhizosphere soil among different plantations.The results of high throughput sequencing showed that the rhizosphere soil bacterial diversity of R.pseudoacacia plantation was highest among four plantations,and the observed species number,Chao1 index,Shannon index and Simpson index were 1 828.489,2 602.806,8.917 and 0.95,respectively,its Simpson index was lowest among four plantations.Observed species number (1 703.36) in U.pumila plantation,Chao1 index (2 161.69) in F.velutina plantation was lowest among four plantations.The rhizosphere soil bacterial Shannon index of A.altissima was lowest among four plantations with 8.73,and Simpson index was highest with 0.98.The results showed available P (1.17 mg· kg-1),K (163 mg · kg-1),N (30.47 mg · kg-1),and organic matter (4.4 g · kg-1) content of U.pumila plantation were lowest among four plantations.Available P (3.47 mg · kg-1) content of R.pseudoacacia plantation was highest.Soil pH (8.52),water content (13.10％),Available K (330.00 mg · kg-1),N (48.63 mg· kg-1),and organic matter (74.83 g · kg-1) content of A.altissima plantation were highest,especially,soil water content and organic matter (74.83 g · kg-1) content were significantly higher than other 3 plantations.The results of correlation analyses showed that there were significant correlations between the content of conductivity,soil water content,available P,N,organic matter and bacterial diversity among four plantations,but the correlation between pH and bacterial diversity was not significant.[Conclusion] The bacterial structure in rhizosphere soil of different plantations was similar,but there was a significant difference in the relative abundance of some bacteria at phylum level.The rhizosphere soil bacterial diversity of R.pseudoacacia was highest among four plantations.Conductivity,soil water content,and available P,N,K content were the main soil factors that affect the soil bacterial structure and diversity.But further research is also needed to obtain more information in soil microorganisms.%[目的]研究黄河三角洲4个不同树种人工林根际土壤细菌群落结构及多样性,揭示人工林改善土壤生产力的微生物学机制,为人工林的栽培和管理提供理论依据.[方法]应用高通量测序技术,比较臭椿、榆树、绒毛白蜡和刺槐4种人工林根际土壤细菌群落结构及多样性,并结合根际土壤理化性质进行相关性分析.[结果]1)臭椿、榆树、白蜡和刺槐人工林根际土壤细菌分别有27、26、28和28门,酸杆菌门、变形菌门和放线菌门3门细菌在4种人工林根际土壤中相对丰度大于10％,是根际土壤中的优势群落;硝化螺旋菌门、绿弯菌门、浮游菌门、芽单胞菌门和疣微菌门5门细菌相对丰度超过1％,是根际土壤中的主要群落.4种人工林根际土壤中变形菌门、WS3、蓝藻菌门、广古菌门、厚壁菌门、OD1和软皮菌门7门细菌丰度差异显著.2)4种人工林中刺槐根际土壤细菌多样性最高,物种数、Chao1指数、Shannon多样性指数和Simpson指数分别为1 828.49、2 602.81、8.92和0.95.榆树根际土壤细菌物种数和白蜡根际土壤细菌Chao1指数最低,分别为1 703.36和2 161.69.臭椿根际土壤细菌Shannon指数最低,Simpson指数最高,分别为8.73和0.98.3)榆树根际土壤碱解氮、有效磷、速效钾和有机质含量最低.刺槐根际土壤有效磷含量为3.47 mg· kg-,显著高于其他3种人工林.臭椿根际土壤pH、碱解氮、速效钾和有机质含量最高,分别为8.52、48.63 mg· kg-、330.27 mg·kg-1和74.83 g·kg-1,土壤含水量和有机质含量显著高于其他3种人工林.4)人工林根际土壤电导率、含水量、碱解氮、有效磷、速效钾和有机质含量与根际土壤细菌多样性相关关系显著,土壤pH与细菌多样性指数无显著相关关系.[结论]黄河三角洲4种人工林根际土壤细菌结构相似,但部分细菌丰度差异显著;刺槐根际土壤细菌多样性最高.土壤电导率、碱解氮、有效磷和速效钾含量是细菌结构和多样性的主要影响因素.
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