Copper accumulation process and rhizosphere mechanism under different water regime in riparian wetland of Poyang Lake, China

Abstract Purpose Conducting research about the metal accumulation process of wetland plants and relevant rhizosphere mechanism can better understand the biogeochemical behavior of metals in riparian wetland. However, little relative information is available for riparian wetland. Methods In this study, we explored the copper accumulation process of dominant plant of Artemisia and rhizosphere mechanism under different water regime (flooding condition [FC], dry condition [DC] and alternate dry and flooding condition [DFC]) in riparian wetland of Poyang Lake.Results The result indicated that continuous or intermittent flooding may impede the accumulation and transformation of Cu by Artemisia. The correlation and multivariate analysis indicated that rhizosphere pH, Cu fraction and iron plaque on root surface can significantly influence Cu accumulation process. The transformation of exchangeable fraction to carbonate bound fraction and organic fraction under DFC and FC treatments may impede the accumulation of Cu in Artemisia. Formation of iron plaque under DFC and DC treatments can enhance the Cu accumulation in roots, but impede the translocation of Cu to aboveground tissues. Higher rhizosphere pH under DFC and FC treatments may impede the translocation of Cu by enhancing formation of iron plaque. Additionally, the growth status, bioaccumulation factor, translocation factor and root/aerial Cu content indicated that Artemisia can accumulate quantitative Cu in roots, but not suitable for phytoextracting Cu contaminated soil because of significant decrease of biomass with Cu addition, especially under DFC and FC treatments. Conclusion Altogether, our results indicate that Cu accumulation processes and ability is impeded by DFC and FC treatments.