Department of Biology, Faculty of Science, Urmia University, Urmia, Iran.
Department of Biology, Faculty of Science, Urmia University, Urmia, Iran.
Ecotoxicol Environ Saf. 2021 Jan 15;208:111607. doi: 10.1016/j.ecoenv.2020.111607. Epub 2020 Nov 13.
The present study aimed to explore the effect of synthetic and naturally occurring chelators, EDTA and citric acid (CA), respectively, on changes in physiological and biochemical factors including cell death, level of mercury ions accumulation, malondialdehyde (MDA) content, total phenol and total flavonoids, anthocyanins and DPPH free radical scavenging activity, in the leaves of okra (Abelmoschus esculentus L.) plants exposed to mercury stress. In addition, polyphenolic compounds profile was assessed by high-performance liquid chromatography. The okras were planted in completely controlled hydroponic conditions (Hoagland solution). After they reached the four-leaf stage, they were treated simultaneously with different concentrations of HgCl, EDTA and CA chelators, and their combination for one month. At the stage of maturity, the physiological and biochemical factors of the plant leaves were measured. The results showed that with the application of higher concentration of HgCl, cell death, level of shoot and root Hg content and root MDA, total phenols and total flavonoids, anthocyanin content, and DPPH free radical scavenging activity were increased. Also, the results indicated that okra plants have high biomass and a high rate of Hg mobilization and accumulation in the shoot versus the roots (TF=2.152 for the plants treated with 60 mg L Hg), hence, can be considered as Hg hyperaccumulator plant for the phytoremediation of Hg-polluted soils and waters. In the Hg-treated plants changes in their phenolic profile were induced, and the increase of chlorogenic acid, rosmaric acid, apigenin, quercetin and rutin content was observed. The application of EDTA and CA improved the toxic effects of Hg, by modifying phenolic compounds, chelating Hg, and its proper compartmentation, while EDTA outperformed CA in this respect. Based on the results, it could be concluded that due to the high biomass and growth of okra in the presence of Hg, this plant is suitable for phytoremediation of soil and water contaminated with mercury. In addition, EDTA and CA can play a significant role in removing this toxic metal through transferring it from the culture medium to the plant.
本研究旨在探讨合成螯合剂 EDTA 和天然螯合剂柠檬酸（CA）对汞胁迫下蕹菜叶片生理生化因素变化的影响，这些因素包括细胞死亡、汞离子积累水平、丙二醛（MDA）含量、总酚和总类黄酮、花青素和 DPPH 自由基清除活性。此外，还通过高效液相色谱法评估了多酚化合物的特征。蕹菜在完全控制的水培条件（Hoagland 溶液）中种植。当它们长到四叶期时，同时用不同浓度的 HgCl、EDTA 和 CA 螯合剂及其组合处理一个月。在成熟阶段，测量植物叶片的生理生化因素。结果表明，随着 HgCl 浓度的增加，细胞死亡、茎叶汞含量和根 MDA、总酚和总类黄酮、花青素含量以及 DPPH 自由基清除活性均增加。此外，结果表明，蕹菜植株具有高生物量和高汞在地上部的迁移和积累率，而根部（TF=2.152，用 60 mg L Hg 处理的植株），因此可以作为 Hg 超积累植物，用于受 Hg 污染的土壤和水的植物修复。在受 Hg 处理的植物中，其酚类特征发生了变化，观察到绿原酸、迷迭香酸、芹菜素、槲皮素和芦丁含量增加。EDTA 和 CA 的应用改善了 Hg 的毒性作用，通过改变酚类化合物、螯合 Hg 及其适当的区室化，而 EDTA 在这方面优于 CA。基于这些结果，可以得出结论，由于蕹菜在 Hg 存在下具有高生物量和生长，因此该植物适合用于受 Hg 污染的土壤和水的植物修复。此外，EDTA 和 CA 可以通过将这种有毒金属从培养基转移到植物中来发挥重要作用，从而去除这种金属。
