NTA与EDTA联合施用对茼蒿富集土壤重金属的影响

为了解非生物螯合剂EDTA与生物螯合剂NTA协同施用对土壤重金属污染修复的效果,采用盆栽方法,研究不同配比螯合物EDTA和NTA施用下,茼蒿对土壤重金属(Pb、Cu和Cd)富集的程度;同时评估了螯合物对茼蒿叶绿素、维生素C含量以及土壤营养元素流失程度的影响。结果表明:处理(EDTA/NTA=2∶1)时,茼蒿根部重金属Pb、Cd含量均最高。处理(EDTA/NTA=1∶1)时,显著促进茼蒿植株对重金属Cu吸收和地上部转运,螯合剂用量最少,协同作用最好。不同配比的螯合剂处理均对茼蒿产生抑制作用,同时降低茼蒿生理指标叶绿素、维生素C含量。在处理(EDTA=1),叶绿素SPAD、维生素C含量分别达到最低值36 mg/100 g和38 mg/100 g。对于淋滤液中营养元素TN而言,处理(NTA=1、EDTA/NTA=1∶2)中TN随着时间推移逐渐减少,第十天均显著低于第一天淋滤液中浓度(p<0.05);第十五天TN流失量在处理(NTA=1)下降最多,达到51.6%,活化效果显著下降。淋滤液中营养元素TP,螯合剂活化效果高低依次为:处理(EDTA/NTA=1∶1)>处理(EDTA=1)>处理(EDTA/NTA=2∶1)>处理(EDTA/NTA=1∶2)>处理(NTA=1)。结合茼蒿生理指标、重金属提取效果以及氮磷流失量,推荐最佳的螯合剂施用配比为处理(EDTA/NTA=2∶1)。

Effects of Application of NTA and EDTA on Accumulation of Soil Heavy Metals in Chrysanthemum

In order to find out the effect of non-bio chelating agent EDTA and bio-chelating agent NTA on soil heavy metal pollution, the effects of different ratios of chelating agent NTA and EDTA on soil heavy metals (Pb, Cu and Cd), the effects of chelating on contents of chlorophyll and vitamin C and the degree of soil nutrient loss were evaluated. Results show that the contents of Pb and Cd are the highest in the roots of chrysanthemum in the treatment (EDTA/NTA=2:1). The treatment (EDTA/NTA=1:1) is the best in chelating agent ratio for synergistic effect, which can significantly promote chrysanthemum on heavy metal Cu uptake and transport to aboveground. The chrysanthemum is inhibited by all chelating agents treatments, while the contents of chlorophyll and vitamin C of the chrysanthemum physiological indexes decrease. In the treatment (EDTA=1), chlorophyll SPAD and vitamin C contents reach a minimum of 36 and 38mg/100g, respectively. The nutrient element TN in the leachate gradually decreases with the time, and in the tenth day is significantly lower than the leaching rate of the first day (p <0.05) in the treatments (NTA=1, EDTA/NTA=1:2). The nutrient element TN decreases most, reaching 51.6%, and the activation effect decreases significantly in the fifteenth day in treatment (NTA=1). Results show the order of treatment(EDTA/NTA=1:1) > treatment (EDTA=1) > treatment (EDTA/NTA=2:1) > treatment (EDTA/NTA=1:2) > treatment (NTA=1). Treatment (EDTA/NTA=2:1) is recommended for the chelating agent ratio with better physiological parameters, more heavy metal extraction and less nitrogen and phosphorus loss.