School of Life Sciences, Taizhou University, Linhai 317000, China.
J Environ Sci (China). 2010;22(12):1916-22. doi: 10.1016/s1001-0742(09)60339-9.
Paulownia fortunei has been successfully used in the phytoremediation of many Pb/Zn mine tailings. However, seed germination and young seedlings of P. fortunei rarely occurred in these mine tailings. The physiological responses and detoxific mechanisms of P. fortunei young seedling to Pb, Zn, Cu and Cd stress were investigated. The germinated rate, shoot length, chlorophyll and carotenoid contents in leaves of young seedlings had a great reduction under Zn and Cu treatments, but had little decrease under Pb and Cd treatments. The production rate of O2*-, H2O2 and malondialdehyde (MDA) contents significantly increased in response to added Zn and Cu indicating great oxidative stress for young seedlings, but they had no significant change to added Pb and Cd. Young seedlings had effective detoxific mechanism to Pb and Cd, as antioxidant enzymes activities, phytochelatins (PCs-SH) and proline contents increased with increasing rates of added Pb and Cd. However, young seedlings had un-effective detoxific mechanisms to Zn and Cu stress. Results revealed the heavy metals (such as Cu) that present at low concentrations in mine tailings may be major constraint for the survival of young seedlings.
泡桐已成功应用于多种 Pb/Zn 矿山尾矿的植物修复。然而，在这些矿山尾矿中，泡桐的种子发芽和幼苗很少出现。研究了泡桐幼树幼苗对 Pb、Zn、Cu 和 Cd 胁迫的生理响应和解毒机制。在 Zn 和 Cu 处理下，幼苗的发芽率、茎长、叶片叶绿素和类胡萝卜素含量显著降低，但在 Pb 和 Cd 处理下，发芽率、茎长、叶片叶绿素和类胡萝卜素含量下降幅度较小。O2*-、H2O2 和丙二醛（MDA）含量的产生速率显著增加，表明幼苗受到严重的氧化胁迫，但对添加的 Pb 和 Cd 没有显著变化。幼苗对 Pb 和 Cd 具有有效的解毒机制，随着添加的 Pb 和 Cd 速率的增加，抗氧化酶活性、植物螯合肽（PCs-SH）和脯氨酸含量增加。然而，幼苗对 Zn 和 Cu 胁迫没有有效的解毒机制。结果表明，矿山尾矿中低浓度存在的重金属（如 Cu）可能是幼苗生存的主要限制因素。
