黄河三角洲盐生植被演替与土壤细菌群落结构的关系

Relationship between the Halophyte Vegetation Succession and Soil Bacterial Community Structure in the Yellow River Delta

研究黄河三角洲光板地和4种盐生植被(翅碱蓬、獐茅、白茅和罗布麻)下土壤细菌群落组成,揭示其与盐生植被演替的关系。利用细菌16S r DNA基因文库方法,构建系统发育树,在5个文库中各挑选180个阳性克隆子进行序列测定,并对数据进行统计分析。从光板地、翅碱蓬、獐茅、白茅和罗布麻5个文库中分别得到121、132、150、159、155条有效序列。重盐土壤(翅碱蓬土壤、獐茅土壤)细菌有着最高的Shannon指数和最低的Simpson优势度指数。土壤中检测到变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、酸杆菌门(Acidobacteria)等,共8门。其中变形菌门在5种土样中相对丰度为21.06%,拟杆菌门为11.16%,其他细菌相对丰度皆未超过10%。5种覆被类型下土壤细菌在种群组成上差异明显,但均匀度与丰富度差异较小,变形菌为所研究5种土壤中的优势菌群。当盐生植被处于相同演替阶段时,土壤细菌群落结构具有更大相似性;在不同演替阶段时,土壤细菌群落结构差别较大。

The study was to investigate the soil bacterial community structure of bare land and four kinds of halophyte vegetation(Saline Seepweed, Angiospermae, Imperata and A. venetum) in the Yellow River Delta, aiming at revealing its relationship with halophytic vegetation succession. Phylogenetic trees were constructed by the use of bacterial 16 s r DNA gene library. For each of the five libraries constructed,180 positive clones were picked randomly and sequenced, and the data then were statistically analyzed. A total of 121, 132, 150, 159 and 155 valid sequences were obtained from bare land, Saline Seepweed, Angiospermae, Imperata and A. venetum. The heavy salt soil(Saline Seepweed and Angiospermae) had the highest Shannon index and the lowest Simpson dominance index. Bacteria belonging to 8 phyla were identified, such as Proteobacteria, Bacteroidetes, Acidobacteria. Among them,Proteobacteria accounted for 21.06% and Bacteroidetes accounted for 11.16%, while the other bacterial phyla each accounted for less than 10%. The soil bacterial community structure of the 5 soil bacteria differed significantly, while the evenness and richness had less differences, and Proteobacteria was the advantage microflora. The community structure of soil bacteria had a greater similarity when the halophytic vegetation succession at the same stage; while the differences were significant at the different stage.