Iron plaques have been found to limit the phytoremediation efficiency by reducing iron solubility, while chelating agents can increase the bioavailability of iron from Fe plaques to numerous terrestrial plants. However, the effects of chelating agents on Fe plaques along the As accumulation in aquatic plants remain unknown. In this study, the effects of five chelating agents (EDTA, DTPA, NTA, GLDA, and CA) on the As (As(III) or As(V)), phosphate, and iron uptake by iron plaques and duckweed (Lemna minor) were examined. The results showed that the chelating agents increased the As accumulation in L. minor plants by desorbing and mobilizing As from Fe plaques. The desorption rates of As(V) (As(III)) from the Fe plaques by the chelating agents were 5.26–8.77% (8.70–15.02%), and the plants/DCB extract ratios of As(V) (As(III)) increased from 2.63 ± 0.13 (1.97 ± 0.06) to the peak value of 3.38 ± 0.21 (2.70 ± 0.14) upon adding chelating agents. Besides, the addition of chelating agents increased the uptake of P and Fe by L. minor plants. This work provides a theoretical basis for the remediation of As-contaminated waters by duckweed with the help of chelating agents.

已经发现铁斑通过降低铁溶解度来限制植物修复效率，而螯合剂可以增加铁斑中铁对许多陆生植物的生物利用度。然而，螯合剂对水生植物中砷积累过程中铁斑块的影响仍然未知。在本研究中，五种螯合剂（EDTA、DTPA、NTA、GLDA 和 CA）对铁斑块和浮萍（Lemna minor ) 进行了检查。结果表明螯合剂增加了L. minor的 As 积累植物通过从 Fe 斑块中解吸和动员 As。螯合剂从 Fe 斑块中解吸 As(V) (As(III)) 的速率为 5.26-8.77% (8.70-15.02%)，As(V) (As(III) )) 在添加螯合剂后从 2.63 ± 0.13 (1.97 ± 0.06) 增加到峰值 3.38 ± 0.21 (2.70 ± 0.14)。此外，除了螯合剂的增加磷，铁被吸收L.轻微植物。该工作为浮萍在螯合剂的作用下修复As污染水体提供了理论依据。