Influence of [S, S]-EDDS on Phytoextraction of Copper and Zinc by Elsholtzia Splendens From Metal-Contaminated Soil

Abstract

Two pot experiments were conducted to investigate the time course effects of the (S, S)-N, N′-ethylenediamine disuccinic acid (EDDS) addition to contaminated soil on the uptake of Cu and Zn by the Cu accumulator Elsholtzia splendens and on plant Cu and Zn concentrations at different growth stages. EDDS increased the amounts of Cu and Zn soluble in the soil, taken up by plants, concentrated in the xylem sap, and translocated from roots to stems and leaves. The increase in soil-soluble metals, especially Cu, resulted in a corresponding increase in metal concentrations in the xylem sap and leaves. The addition of EDDS to the soil increased plant Cu and Zn concentrations, especially in the leaves, and changed the proportions of Cu and Zn taken up by different plant parts. The proportions of Cu and Zn taken up by the roots were higher than by the leaves of control plants, but EDDS-treated plants showed the opposite trend. EDDS exerted greater effects at the end of the vegetative growth stage than at the start of the flowering or reproductive stages.

KEY WORDS:

• ethylenediamine disuccinic acid (EDDS)
• Elsholtzia splendens
• growth stage
• Cu uptake
• Zn uptake

ACKNOWLEDGEMENTS

The authors thank the Major State Basic Research and Development Program of PR China (grant 2002CB410809), the State High-tech Research and Development Program of PR China (grant 2004AA649050), and the Program of Innovative Engineering of the Chinese Academy of Sciences (grant KZCX3-SW-429–2) for financial support.