Barocsi Attila, Csintalan Zsolt, Kocsanyi Laszlo, Dushenkov Slavik, Kuperberg J Michael, Kucharski Rafal, Richter Peter I
Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary.
Int J Phytoremediation. 2003;5(1):13-23. doi: 10.1080/16226510390856448.
Soil phytoextraction is based on the ability of plants to extract contaminants from the soil. For less bioavailable metals, such as Pb, a chelator is added to the soil to mobilize the metal. The effect can be significant and in certain species, heavy metal accumulation can rapidly increase 10-fold. Accumulation of high levels of toxic metals may result in irreversible damage to the plant. Monitoring and controlling the phytotoxicity caused by EDTA-induced metal accumulation is crucial to optimize the remedial process, i.e. to achieve maximum uptake. We describe an EDTA-application procedure that minimizes phytotoxicity by increasing plant tolerance and allows phytoextraction of elevated levels of Pb and Cd. Brassica juncea is tested in soil with typical Pb and Cd concentrations of 500 mg kg-1 and 15 mg kg-1, respectively. Instead of a single dose treatment, the chelator is applied in multiple doses, that is, in several small increments, thus providing time for plants to initiate their adaptation mechanisms and raise their damage threshold. In situ monitoring of plant stress conditions by chlorophyll fluorescence recording allows for the identification of the saturating heavy metal accumulation process and of simultaneous plant deterioration.
土壤植物提取技术基于植物从土壤中提取污染物的能力。对于生物有效性较低的金属，如铅，需向土壤中添加螯合剂以活化金属。这种效果可能很显著，在某些物种中，重金属积累量可迅速增加10倍。高浓度有毒金属的积累可能会对植物造成不可逆转的损害。监测和控制由乙二胺四乙酸（EDTA）诱导的金属积累所导致的植物毒性，对于优化修复过程（即实现最大吸收量）至关重要。我们描述了一种EDTA施用程序，该程序通过提高植物耐受性将植物毒性降至最低，并允许对高水平的铅和镉进行植物提取。在铅和镉典型浓度分别为500毫克/千克和15毫克/千克的土壤中对印度芥菜进行了测试。螯合剂采用多次剂量施用，而非单次剂量处理，即分几次少量添加，从而为植物启动其适应机制并提高其损伤阈值提供时间。通过叶绿素荧光记录对植物胁迫状况进行原位监测，有助于识别饱和重金属积累过程以及同时发生的植物退化情况。
