Abstract
Characteristics of copper (Cu) -resistant bacterial communities in a rhizosphere and non-rhizosphere of a ditch reed, Phragmites sp., in highly Cu-contaminated area near a copper mine were investigated. In the rhizosphere, multiplication of bacteria, particularly non-resistant bacteria, was promoted as compared with the nonrhizosphere. The properties of bacterial community in the rhizosphere were largely different from those in the nonrhizosphere in Cu sorption. growth rate, and exopolymers production. Both Cu-resistant bacteria and non-resistant bacteria in the rhizosphere grew more rapidly in a medium than those in the nonrhizosphere. For almost all the isolates with Cu resistance, exopolymer productions were prompted by Cu stimuli expecially for the Cu-resistant bacteria from the rhizosphere. The adverse effect of Cu on the growth rate, was found to be small for the Cu-resistant bacteria producing exopolymers in large quantity, suggesting the involvement of exopolymers in detoxification of Cu.
