Laboratoire des Plantes Extremophiles, Centre de Biotechnologie de Borj-Cédria, BP 901, Hammam Lif, 2050, Tunisia,
Environ Sci Pollut Res Int. 2014 Jun;21(12):7607-15. doi: 10.1007/s11356-014-2690-5. Epub 2014 Mar 8.
The low bioavailability of Pb and low number of Pb-tolerant plant species represent an important limitation for Pb phytoextraction. It was recently suggested that halophyte plant species may be a promising material for this purpose, especially in polluted salt areas while Pb mobility may be improved by synthetic chelating agents. This study aims to evaluate Pb extraction by the halophyte Sesuvium portulacastrum in relation to the impact of EDTA application. Seedling were cultivated during 60 days on Pb artificially contaminated soil (200, 400, and 800 ppm Pb) in the presence or in the absence of EDTA (3 g kg(-1) soil). Results showed that upon to 400 ppm, Pb had no impact on plant growth. However, exogenous Pb induce a decrease in shoot K(+) while it increased shoot Mg(2+) and had no impact on shoot Ca(2+) concentrations. Lead concentration in the shoots increased with increasing external Pb doses reaching 1,390 ppm in the presence of 800 ppm lead in soil. EDTA addition had no effect on plant growth but strongly increased Pb accumulation in the shoot which increased from 1,390 ppm in the absence of EDTA to 3,772 ppm in EDTA-amended plants exposed to 800 ppm exogenous Pb. Both Pb absorption and translocation from roots to shoots were significantly enhanced by EDTA application, leading to an increase in the total amounts of extracted Pb per plant. These data suggest that S. portulacastrum is very promising species for decontamination of Pb(2+)-contaminated soil and that its phytoextraction potential was significantly enhanced by addition of EDTA to the polluted soil.
重金属铅的生物可利用性低，且耐铅植物种类较少，这是铅的植物提取的一个重要限制因素。最近有人提出，盐生植物可能是一种很有前途的材料，尤其是在污染的盐区，同时，通过合成螯合剂可以提高铅的迁移率。本研究旨在评估盐生植物海蓬子（Sesuvium portulacastrum）在应用 EDTA 的情况下对铅的提取效果。在人工污染土壤（200、400 和 800 ppm Pb）中，幼苗在不存在或存在 EDTA（3 g kg(-1)土壤）的情况下培养 60 天。结果表明，在 400 ppm 时，Pb 对植物生长没有影响。然而，外源 Pb 会导致地上部 K(+)减少，而增加 Mg(2+)，对地上部 Ca(2+)浓度没有影响。随着外部 Pb 剂量的增加，地上部 Pb 浓度增加，在土壤中存在 800 ppm Pb 的情况下，达到 1390 ppm。EDTA 的添加对植物生长没有影响，但强烈增加了地上部 Pb 的积累，在不存在 EDTA 的情况下，积累量从 1390 ppm 增加到 EDTA 处理、暴露于 800 ppm 外源 Pb 的植物中 3772 ppm。EDTA 的应用显著促进了 Pb 的吸收和从根部向地上部的转运，导致每株植物提取的 Pb 总量增加。这些数据表明，海蓬子是一种很有前途的修复 Pb(2+)-污染土壤的物种，通过向污染土壤添加 EDTA，其植物提取潜力得到了显著增强。
