A rhizobox experiment was conducted to compare iron （Fe） oxidation and changes of pH, redox potential （Eh） and fractions of zinc （Zn） and lead （Pb） in rhizosphere and non-rhizosphere soils of four emergent-roo...A rhizobox experiment was conducted to compare iron （Fe） oxidation and changes of pH, redox potential （Eh） and fractions of zinc （Zn） and lead （Pb） in rhizosphere and non-rhizosphere soils of four emergent-rooted wetland plants （Echinodorus macrophyllus, Eleocharis geniculata, Hydrocotyle vulgaris and Veronica serpyllifolia） with different radial oxygen loss （ROL） from roots. The results indicated that all these wetland plants decreased pH and concentration of Fe（II） but increased the Eh in the rhizosphere soils. Pb and Zn were transformed from unstable fractions to more stable fractions in the rhizosphere soils, so decreasing their potential metal mobility factors （MF）. Among the four plants, E. macrophyllus, with the highest ROL and root biomass, possessed the greatest ability in formation of Fe plaque and in the reduction of heavy metal MFs in the rhizosphere soil. Wetland plants, with higher ROLs and root biomass, may thus be effective in decreasing potential long-term heavy metal bioavailabilities.展开更多
基金Supported by the National Natural Science Foundation of China(No.30570345)the NSFC-Guangdong Joint Fund,China(No.U0833004)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20558097)the Fundamental Research Funds for the Central Universities of China(No.10lgzd10)
文摘A rhizobox experiment was conducted to compare iron （Fe） oxidation and changes of pH, redox potential （Eh） and fractions of zinc （Zn） and lead （Pb） in rhizosphere and non-rhizosphere soils of four emergent-rooted wetland plants （Echinodorus macrophyllus, Eleocharis geniculata, Hydrocotyle vulgaris and Veronica serpyllifolia） with different radial oxygen loss （ROL） from roots. The results indicated that all these wetland plants decreased pH and concentration of Fe（II） but increased the Eh in the rhizosphere soils. Pb and Zn were transformed from unstable fractions to more stable fractions in the rhizosphere soils, so decreasing their potential metal mobility factors （MF）. Among the four plants, E. macrophyllus, with the highest ROL and root biomass, possessed the greatest ability in formation of Fe plaque and in the reduction of heavy metal MFs in the rhizosphere soil. Wetland plants, with higher ROLs and root biomass, may thus be effective in decreasing potential long-term heavy metal bioavailabilities.
