NTA对玉米体内Cu Zn的积累及化学形态的影响

在重金属污染土壤的植物修复研究中，人工合成络合剂被广泛用来提高植物提取效率。通过向多金属复合污染土壤中加入氨三乙酸（NTA）进行螯合诱导植物提取的研究，并运用化学试剂逐步提取法研究了NTA对玉米根、茎和叶中Cu、Zn化学形态分布的影响。结果表明，Cu和Zn在玉米体内化学形态分布特征与其吸收和富集重金属能力密切相关，NTA能显著促进Cu和Zn在玉米体内的吸收和积累并且影响重金属化学形态的分布。玉米根中，Cu和Zn以水提取态为主，有利于金属离子从根部向地上部迁移；在茎和叶中，以氯化钠提取态、醋酸提取态和水提取态为主要形态，以多种有机螯合物的形式存在，是其耐受重金属毒性的重要机理之一。

Influence of NTA on Accumulation and Chemical Form of Copper and Zinc in Maize

In the phytoremediation research, synthetic chelating agents have been extensively used in enhancing the ability of uptake and accumulation of plant from heavy metals contaminated soils. The sequential chemical extraction method was adopted to study the chemical form of Cu and Zn in the roots, stems and leaves of maize (Zea mays L.) growing on multi-element contaminated soil with the addition of the chelating agent NTA. The results showed that, the chemical form of Cu and Zn had a close relationship with the ability of heavy metal resistance and accumulation in maize. NTA could significantly promote maize to uptake and accumulate Cu and Zn and affect their chemical form distribution in maize tissues. Water-extractable form of Cu and Zn were predominant in roots, whereas other forms were low in the content, which was favorable for heavy metal transporting from roots to shoots in maize. However, NaCl, HAc and water-extractable forms of Cu and Zn were predominant in stems and leaves, indicating that they were coordinated to produce multivalent metal organic acid complexes, which was possibly main mechanism of resisting metal toxicity for maize.