Abstract: The present study was conducted to evaluate the composition and diversity of rhizosphere bacterial community of Pontedeira cordata, Canna indica and Thalia dealbata in verticalflow constructed wetland during operation in summer and autumn. All parameters were measured using PCR-DGGE and DNA sequencing technology. Results indicated that the types and quantity of microorganisms in the rhizosphere of the three plants were not all the same. Shannon indexes of P. cordata, C. indica and T. dealbata rhizosphere microorganisms were 2.91, 2.96 and 2.90, respectively, further explaining that the root of C. indica in the verticalflow constructed wetland could better enrich the microorganisms around the substrate and increased the diversity of bacterial community. The similarity analysis of rhizosphere microorganisms of the three plants showed that there was seasonal difference of microbial community structure. The rhizosphere microorganisms of C. indica and T. dealbata had higher similarity (>65%), indicating that the roots of these two plants were similar in the aggregation of microorganisms. Diversity of microbial community structure indicated that rhizosphere microbial community of the three plants in verticalflow constructed wetland during the experimental period belonged to 8 classes: α-Proteobacteria (14.37%), β-Proteobacteria (38.13%), γ-Proteobacteria (6.87%), ε-Proteobacteria (16.86%), δ-Proteobacteria (6.87%), Actinobacteria (8.76%), Bacteroidetes (4.38%), and Nitrospira (3.75%). β-Proteobacteria was the main group of bacteria enriched by the various plants in the vertical-flow constructed wetland during the experimental period. This experiment provides some theoretical basis for the species optimization of artificial wetland system in the future.

Key words: larval Japanese Halfbeak, geographically weighted regression, habitat suitability index, Bohai Sea