Pedosphere 18(6): 758--765, 2008
ISSN 1002-0160/CN 32-1315/P
©2008 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Ectomycorrhizal fungus-induced changes of Cu and Cd speciation in the rhizosphere of Chinese pine seedlings |
HUANG Yi , LI Ting, HUANG Zhi-Ji and FEI Ying-Heng |
| College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China). E-mail: yhuang@pku.edu.cn |
| ABSTRACT |
| To understand the role of ectomycorrhizas in improving the tolerance of its host to excessive heavy metals in soil, this study was conducted to exam the patterns of four fractions (the exchangeable, the carbonate-bound, the Fe-Mn oxidebound and the organically bound) of both Cu and Cd in the rhizosphere of Chinese pine (Pinus tabulaeformis) seedlings grown in excessive Cu and Cd environment. The results showed that the speciation of Cu and Cd in the rhizosphere was significantly influenced by inoculation of ectomycorrhizal fungus Boletus edulis. Compared to the rhizosphere, the content of exchangeable Cu slightly decreased in the mycorrhizosphere of the seedlings grown in 166 and 400 mg kg-1 Cu contaminated soil, whereas the exchangeable Cd in the mycorrhizosphere decreased remarkably to only 33% and to 60% that of the rhizosphere at 0.75 and 1.50 mg kg-1 Cd levels, respectively. These indicate the potential capacity of mycorrhizas to alleviate the damage of heavy metals to the host plants by reducing the bioavailability of heavy metals in soil. Distribution of the 4 tested fractions of Cu and Cd at different contamination levels showed that there was a strong tendency of changing from loosely associated fractions to strongly associated fractions in the mycorrhizosphere. The most stable Cd fraction, organically bound Cd, was significantly larger in the mycorrhizosphere than in the rhizosphere at different Cd contamination levels. This phenomenon was also observed for Cu but the difference was not statistically significant. |
| Key Words: Chinese pine, ectomycorrhizal fungus, heavy metal speciation, mycorrhizosphere, rhizosphere |
| Citation: Huang, Y., Li, T., Huang, Z. J. and Fei, Y. H. 2008. Ectomycorrhizal fungus-induced changes of Cu and Cd speciation in the rhizosphere of Chinese pine seedlings. Pedosphere. 18(6): 758-765. |
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