黄芥-螯合剂修复对土壤Pb和磷酸酶活性的影响

Effect of yellow mustard and chelating agents treatment on Pb content and phosphatase activity in the soil

通过盆栽实验进行两种螯合剂(草酸、乙二胺四乙酸二钠(EDTA))诱导黄芥修复重金属Pb污染土壤,探讨了土壤中Pb总量变化、黄芥生长及对土壤中磷酸酶活性和有效磷含量的影响,并通过回归分析,研究了Pb含量与磷酸酶活性和有效磷与磷酸酶活性的相关性。草酸和EDTA质量摩尔浓度分别为2和5 mmol kg-1,Pb质量分数最低,对土壤的修复效果好。草酸促进了黄芥的生长,而EDTA降低了黄芥的生物量。草酸和EDTA诱导修复土壤,对磷酸酶活性都有促进作用,分别达到了85.71%和128.57%。加入EDTA,磷酸酶的活性随Pb质量分数的增加而减小。草酸和EDTA修复后,土壤中有效磷的质量分数增加,最大有效磷质量分数分别为124.48和105.62 mg kg-1。在加入草酸后,有效磷含量与磷酸酶的相关性呈现出极显著关系(P<0.01);添加EDTA,两者呈正相关(P=0.088 3)。结果表明,EDTA对Pb的活化能力强于草酸,EDTA对酶活性的促进效果优于草酸,在促进磷酸酶将不可利用的磷转化为有效态时,草酸优于EDTA。磷酸酶可作为评价草酸和EDTA修复重金属Pb污染土壤能力的重要指标。

In this article,pot experiments were carried out by oxalic acid and EDTA induced phyto-remediation of Pb contaminated soil by yellow mustard.Changes of Pb content,yellow mustard biomass,the effects of Pb content and yellow mustard biomass on phosphatase activity and phosphorus content in the polluted soil and the correlation between phosphatase activity and Pb content through regression analysis were investigated.When the concentration of oxalic acid and EDTA were 2 and 5 mmol kg-1,respectively,the concentration of Pb in the soil reached the lowest and had a better soil remediation result.The biomass of yellow mustard increased under adding oxalic acid and decreased under adding EDTA.Oxalic acid and EDTA induced phytoremediation could increase the activity of phosphatase which reached 85.71% and 128.57%,respectively.After adding EDTA,phosphatase activity decreased with increasing of Pb content.After oxalic acid and EDTA induced phytoremediation,the available phosphorus increased and the maximum content were 124.48 and 105.62 mg kg-1,respectively.After the addition of oxalic acid,the available phosphorus and phosphatase showed a very significant relevance（P＆lt;0.01）.After adding EDTA,available phosphorus and phosphatase had a positive correlation（P=0.088 3）.The activity of EDTA on Pb was stronger than that of oxalic acid,the phosphatase activity under EDTA was better than that under oxalic acid.Not Available phosphorus could be changed to available phosphorus by Phosphatase under Oxalic acid better than that under EDTA.The phosphatase activity could be used as an important indicator of evaluating the remediation ability of oxalic acid and EDTA based on Pb contaminated soil.