College of Resources, Sichuan Agricultural University, 211 Huimin Road, Chengdu, 611130, Sichuan, China.
CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
Environ Sci Pollut Res Int. 2022 Jan;29(4):6184-6193. doi: 10.1007/s11356-021-15476-z. Epub 2021 Aug 26.
Chelant-assisted phytoremediation may modify plant rhizosphere, which is closely related to heavy metal (HM) accumulation in plants. This work focused on the effects of nitrilotriacetic acid (NTA) on rhizosphere characteristics to investigate the mechanisms of lead (Pb) accumulation in Athyrium wardii (Hook.) Makino with exposure to 800 mg kg Pb. After NTA application, Pb accumulation in the underground part of A. wardii increased by 14.3%, accompanying with some changes for the rhizosphere soils. Soil pH decreased by 0.37 units, and the dissolved organic carbon (DOC) content in the rhizosphere soils significantly increased by 7.6%. The urease, acid phosphatase, and catalase activities in the rhizosphere soils significantly increased by 104.8%, 19.7%, and 27.1%, respectively. However, a slight inhibition on microbial activities was observed in the rhizosphere of A. wardii after NTA application. Soil respiration decreased by 8.9%, and microbial biomass carbon decreased by 8.9% in the rhizosphere soils, indicating that NTA addition might recruit some microorganisms to maintain rhizosphere functions in Pb-contaminated soils while inhibiting others with low tolerance to Pb. Results suggest that lower pH, more DOC exudation, and higher soil enzyme activities after NTA application contributed to the increase of Pb accumulation in A. wardii. This study gave some preliminary evidence for NTA-assisted Pb remediation by A. wardii by modifying rhizosphere characteristics.
螯合剂辅助植物修复可能会改变植物根际，这与重金属（HM）在植物中的积累密切相关。本研究重点研究了氮三乙酸（NTA）对根际特征的影响，以研究在 800mgkg Pb 暴露下，蹄盖蕨（Athyrium wardii（Hook.）Makino）积累铅的机制。在 NTA 应用后，蹄盖蕨地下部分的 Pb 积累增加了 14.3%，同时根际土壤也发生了一些变化。土壤 pH 值下降了 0.37 个单位，根际土壤中溶解有机碳（DOC）含量显著增加了 7.6%。根际土壤中的脲酶、酸性磷酸酶和过氧化氢酶活性分别显著增加了 104.8%、19.7%和 27.1%。然而，在 NTA 应用后，蹄盖蕨根际的微生物活性受到轻微抑制。土壤呼吸降低了 8.9%，根际土壤中微生物生物量碳降低了 8.9%，表明 NTA 的添加可能会招募一些微生物来维持受 Pb 污染土壤的根际功能，同时抑制那些对 Pb 耐受性低的微生物。结果表明，NTA 应用后较低的 pH 值、更多的 DOC 分泌和更高的土壤酶活性有助于蹄盖蕨中 Pb 积累的增加。本研究为 NTA 辅助蹄盖蕨修复 Pb 污染提供了一些初步证据，通过改变根际特征来实现。
