Responses of Lolium multiflorum Lam. Rhizosphere Environment to Polychloro-Organic Pollutants

In order to investigate the mechanism of rhizosphere phytoremediation,the response of a Lolium multiflorum Lam.rhizosphere environment to polychloro-organic pollution(PCOPs) was investigated by modeling the soil-plant system in root-boxes.Compared with the control,the contents of PCOPs in the soil varied with distance from the Lolium multiflorum Lam.rhizosphere.The concentration variation of PCOPs in the soils was consistent with the absorption properties of the Lolium multiflorum Lam.to the PCOPs.The trend exhibited was that the PCOPs were transferred from the soils to the Lolium multiflorum Lam.rhizosphere environment soils.At the absorption peak period,the contents of HCB in the rhizosphere,near the rhizosphere and far from the rhizosphere were 0.313,0.219 and 0.207 mg/kg,respectively,and the contents of p,p′-DDT were 0.351,0.230 and 0.221 mg/kg,respectively.The PCOPs absorption degree in the underground part of the Lolium multiflorum Lam.was significantly higher than that in the aboveground part.The microorganisms grown in the soils greatly influenced the absorption of PCOPs by Lolium multiflorum Lam.At the end of the pot experiment,the contents of HCB in the aboveground and underground parts of the plant were 0.716 and 0.078 mg/kg,respectively,and the contents of p,p′-DDT were 0.745 and 0.065 mg/kg,respectively.It was also concluded that the Lolium multiflorum Lam.could both absorb and degrade PCOPs in the soil environment.In the different treatments,the enzyme activity,pH and organic matter concentrations varied from each other.These variations were much more significant for soils in the Lolium multiflorum Lam.rhizosphere environment than for the soils far from the rhizosphere environment.