Abstract

Purpose

Combining biodegradable chelating agents with phytoextraction is an efficient technique to amend metal-contaminated soils, but most studies have addressed remediation efficiency rather than a comprehensive understanding of the interactions among plant stress, metal accumulation, and metal bioavailability. This study aimed to investigate the effects of biodegradable chelating agents on improving the efficiency of phytoextraction for cobalt (Co)-contaminated soil by sweet alyssum (Lobularia maritima (L.)) and to explore the interrelationships among plant stress, Co accumulation, and Co bioavailability.

Materials and methods

Sweet alyssum (three plants per pot) was grown in pots containing soil with Co added at 0, 40, and 60 mg kg⁻¹, respectively. After 70 days of growth, we added four biodegradable chelating agents (EDDS, NTA, CA, and OA) at various concentrations (0, 2.5, 5.0, and 7.5 mmol kg⁻¹). The plants were harvested after 7 days, and the biomass, reactive oxygen species (ROS) parameters, Co concentrations of the shoot and root, and available Co content in the soil were analyzed.

Results and discussion

The results demonstrate that chelating agents significantly (p < 0.05) improved the phytoextraction capability of sweet alyssum and influenced plant growth and stress. The capability of EDDS to activate Co was higher than that of other chelating agents at identical concentrations in Co-contaminated soils. Furthermore, we observed that a moderate concentration (40 mg kg⁻¹) of Co could promote plant growth and that high concentrations of Co (60 mg kg⁻¹) and EDDS (7.5 mmol kg⁻¹) cause enhanced stress to plant growth, even resulting in lower shoot Co accumulation than that in the moderate EDDS treatment (5.0 mmol kg⁻¹).

Conclusions

The present study demonstrates that the application of EDDS may be a better choice for Co phytoextraction than NTA, CA, and OA; nevertheless, a high concentration of EDDS may enhance the negative effects on plant growth, physiological traits, and Co accumulation.

中文翻译：

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通过可生物降解的螯合剂增强了甜香木（Lobularia maritima（L.）Desv。）对钴（Co）污染土壤的植物提取作用

摘要

目的

将可生物降解的螯合剂与植物提取物结合使用是一种改良金属污染土壤的有效技术，但是大多数研究都针对修复效率，而不是全面了解植物胁迫，金属积累和金属生物利用度之间的相互作用。这项研究旨在研究可生物降解的螯合剂对提高甜菜根（Lobularia maritima（L.））对钴（Co）污染土壤的植物提取效率的影响，并探讨植物胁迫，Co积累和Co之间的相互关系。生物利用度。

材料和方法

甜庭荠（每盆3株植物）在含有土壤的盆中生长用Co加入在0，40，和60毫克千克^-1分别。生长70天后，我们加入了四种浓度（0、2.5、5.0和7.5 mmol kg ^-1）的可生物降解的螯合剂（EDDS，NTA，CA和OA ）。7天后收获植物，分析其生物量，活性氧（ROS）参数，枝条和根的Co浓度以及土壤中的有效Co含量。

结果和讨论

结果表明，螯合剂显着（p  <0.05）改善了甜雪球的植物提取能力，并影响了植物的生长和胁迫。在受Co污染的土壤中，相同浓度的EDDS活化Co的能力高于其他螯合剂。此外，我们观察到中等浓度的Co （40 mg kg ^-1）可以促进植物生长，而高浓度的Co（60 mg kg ^-1）和EDDS（7.5 mmol kg ^-1）会增加植物生长的压力，与中度EDDS处理（5.0 mmol kg ^-1）相比，甚至导致芽Co积累量更低。

结论

本研究表明，EDDS的应用可能比NTA，CA和OA更好地用于植物提取。但是，高浓度的EDDS可能会增强对植物生长，生理特性和Co积累的负面影响。