Abstract:Rhizosphere microorganisms in Myriophyllum aquaticum and Alternanthera philoxeroides were identified and enumerated using Sherlock Microbial Identification System (Sherlock MIS), followed by correlation analyses with environmental factors in Lake Rihu (medium-eutrophic) and River Wocaijiang (high-eutrophic) in Ningbo from August to November 2008. Effects of plant rhizosphere on microbial community composition were significant. The abundance of microbes in the rhizosphere of macrophytes was significantly higher than that in the water column in each month. Community composition of rhizosphere microorganism differed significantly between plant species. In Lake Rihu, the number of microbes in the rhizosphere of M. aquaticum was significantly higher than that of A. philoxeroides. There was no significant difference between the abundances of bacteria in the rhizosphere of two plants, while the abundances of rhizosphere actinomyces and fungi differed significantly between two plant species in River Wocaijiang. Correlations between population size of rhizosphere microbe and environmental factors varied greatly among plant species or sampling sites. Abundance of microbes in the rhizosphere of A. philoxeroides was negatively correlated to chemical oxygen demand (COD), while there was no significant correlation with water temperature, total nitrogen (TN), total phosphate (TP) and Chl.a in Lake Rihu. The number of rhizosphere microbes showed a negative correlation with TP and no significant correlation with other environmental factors in River Wocaijiang. The dominant microbial genera in the rhizosphere of the two macrophytes were Pseudomonas, Micrococcus, Chryseobacterium, Acinetobacter etc. Some other specific functionalmicrobes, e.g. Staphylococcus, Acidovorax, Arthrobacter, were also found in the rhizospheres due to the heterogeneity of environmental conditions and plants. Cluster analyses using Primer 5.0 showed that the similarity of the community structure between summer and autumn was significantly higher than those between the rest seasons where similarities were more dynamic with the value of 21.60%~51.57% in the rhizosphere A. philoxeroides. Diversity of rhizosphere microorganisms was higher in summer than that in autumn in Lake Rihu. In contrast, rhizosphere microbiota was more diverse in autumn than in summer in River Wocaijiang. There was no significant difference of diversity of rhizosphere microbiota between two plants in Lake Rihu. In River Wocaijiang, the diversity of rhizosphere microorganisms of M. aquaticum was higher than that of A. philoxeroides in summer and with the opposite results in autumn. The results obtained in this study indicated that the rhizosphere microbial community structure was affected significantly by the environmental factors and plant species.
陆开宏, 胡智勇, 梁晶晶, 朱津永. 富营养水体中2种水生植物的根际微生物群落特征[J]. 中国环境科学, 2010, 30(11): 1508-1515.
LU Kai-Hong, HU Zhi-Yong, LIANG Jing-Jing, ZHU Jin-Yong. Characteristics of rhizosphere microbial community structure of two aquatic plants in eutrophic waters.. CHINA ENVIRONMENTAL SCIENCECE, 2010, 30(11): 1508-1515.