关键词: 重金属, 金银花, 螯合剂, 有机酸, 植物修复, 植物萃取

Abstract: Aiming at solving the problem of low phytoremediation efficiency of Cd and As polluted soil, chelating agents and organic acids were used to assist plants to extract Cd and As from farmland soil. We examined the effects of different chelating agents \[(ethylenediamine tetraacetic acid (EDTA) and saponin (SAP)\] and organic acids \[citric acid (CA) and malic acid (MA)\] on the extraction of Cd and As in farmland soil by Lonicera japonica Thunb. in a field experiment. The results showed that the four enhancers had no adverse effect on the growth and yield of L. japonica. Different chelating agents and organic acids had different influences on the concentrations of Cd and As in each part of L. japonica. Compared with CK treatment, EDTA application significantly increased stem Cd concentrations in L. japonica by 72.4%. EDTA, SAP, CA and MA significantly increased root As concentrations in L. japonica  by 54.0%, 87.3%, 133.3%, and 39.7%, respectively. The bioconcentration factors of Cd in stems of L. japonica were 13.1-23.3, with a 56.4% increase under EDTA treatment compared with CK treatment. CA and MA significantly enhanced the As bioconcentration factors in stems of L. japonica by 116.7% and 143.3%, respectively. The four enhancers all had significant impacts on the concentrations of Cd and As in the rhizosphere soil. MA had the most significant impact, with a decrease of 32.5% and 31.3% for Cd and As concentration, respectively. Our results provide a theoretical reference for the strengthening of phytoextraction applied for remediation of Cd and As combined polluted farmlands.

Key words: heavy metal, Lonicera japonica Thunb., chelating agent, organic acid, phytoremediation, phytoextraction