可降解螯合剂EDDS诱导植物修复重金属污染土壤的潜力

The potential of biodegradable chelate EDDS for phytoextraction of heavy metals from contaminated soils

用土培试验的方法，研究了螯合剂EDDS和EDTA对苏丹草、玉米、大豆、茼蒿、青菜吸收土壤重金属的影响。结果显示，施用5mmol·kg^-1 EDDS和EDTA可以显著增加供试植物地上部Cu、Pb、Zn和Cd的含量及积累量。EDDS比EDTA具有更强的溶解土壤Cu和增加植物吸收积累Cu的能力；但对土壤Pb的溶解和增加其在植物地上部积累的作用，EDTA大于EDDS。在5种植物中，EDDS对茼蒿Cu含量和积累量的促进作用最大。EDDS处理下茼蒿地上部Cu含量和积累量分别达到973mg·kg^-1和每盆909μg。施用EDDS和EDTA后的5-30d内，土壤水提取态Cu、Pb、Zn和Cd的含量随时间显著下降，尤其是在施用EDDS的土壤中下降更为迅速。上述结果表明，与EDTA相比，可生物降解螫合剂EDDS在诱导植物修复重金属污染特别是Cu污染土壤有很大的潜力，且环境风险较小。

The effects of the application of biodegradable （EDDS） and nondegradable chelate （EDTA） on the uptake of Cu, Zn, Pb and Cd by Sudan grass （ Sorghum sudanense） , corn （Zea mays L. ）, soybean （ Glycine max L. ） , garland chrysanthemum （Chrysanthemum coronarium L. ）, and Chinese cabbage （Brassica chinesis L. ） plants were studied using pot experiments. The results showed that the application of 5 mmol·kg^-1 EDDS and EDTA to the soil significantly increased the concentrations and total uptake amounts of Cu, Zn, Pb and Cd in the shoots of all plant species. EDDS was more effective than EDTA at solubilizing soil Cu and enhancing uptake of Cu by the plants. But for Pb, the EDDS was less effective than EDTA. Among five plant species tested, the uptake of Cu by garland chrysanthemum was highest. The concentration and total uptake amount of Cu by shoots of garland chrysanthemum reached 973 mg·kg^-1 and 909 μg·pot^-1 on day 5 after EDDS application, respectively. The concentrations of water-soluble Cu, Zn, Pb and Cd in soil decreased with time after the chelate application, the decreases were more pronounced in the soil treated with EDDS than with EDTA. The results suggested that EDDS could be regarded as a good chelate candidate for the environmentally safe phytoextraction of heavy metals, particularly for Cu, in contaminated soils.