有机酸对根际土壤中铅形态及其生物毒性的影响

Effects of organic acids on speciation of lead in rhizosphere and their phytotoxicity

采用根袋盆栽试验和连续浸提方法研究外源柠檬酸、EDTA对根际土壤中Pb形态转化及其生物毒性的影响。结果表明,有机酸能明显活化根际土壤中的Pb,高浓度(3 mmol/L)比低浓度(0.5 mmol/L)的柠檬酸对Pb的活化能力强;EDTA在低浓度(0.5 mmol/L)时对Pb的活化能力就很强。柠檬酸、EDTA能增强土壤Pb的毒性,提高小麦根部对Pb的吸收,并促进Pb由根部向地上部转移。

The effect of citric acid or EDTA on the speciation of Pb in soil and phytotoxicity was studied by the method of a sequential extraction technique. The results showed that organic acids significantly mobilized Pb in rhizosphere, and the mobilization of higher concentration of citric acid (3 mmol/L) on Pb was greater than that of low concentration of citric acid (0.5 mmol/L) in rhizosphere. Wheras, EDTA in low dose treatment markedly activated Pb in soils. Citric acid or EDTA was able to intensify phytotoxicity of Pb to wheat, promote Pb accumulation in wheat roots, and increase the transportation of Pb from root to shoot.