School of Metallurgy and Environment, Central South University, Changsha 410083, China.
School of Metallurgy and Environment, Central South University, Changsha 410083, China.
Chemosphere. 2021 Dec;285:131420. doi: 10.1016/j.chemosphere.2021.131420. Epub 2021 Jul 6.
Exogenous application of plant-growth promoting substances in combination with chelators is a common way to enhance the phytoextraction of heavy metals. A pot experiment was used to explore the influences of indole-3-acetic acid (IAA)/gibberellin (GA) alone or together with oxalic acid (OA) on the growth, physiological response, and nutrient contents of hyperaccumulator Sedum alfredii Hance, and cadmium (Cd) and lead (Pb) phytoextraction efficiency. The results showed that a foliar spray of IAA/GA alone or together with OA increased plant growth. The largest shoot biomass with increase by 29.7% was produced by the 50 μmol L IAA combined with 2.5 mmol kg OA (50I+2.5OA) treatment as compared with the control treatment (CK). The presence of IAA and GA enhanced the chlorophyll a, carotenoid, and potassium contents in leaves and decreased the malondialdehyde content. The Cd content in leaf and the translocation factor (TF) value from 50I+2.5OA treatment was increased by 4.29% and 21.4%, and the Pb content in stem and shoot, and the TF of Pb after applying 50 μmol L GA combined with 2.5 mmol kg OA was enhanced by 32.5%, 13.4%, and 57.6%, compared with CK, respectively. The optimal Cd and Pb phytoextraction efficiency occurred from 50I+2.5OA treatment with increase by 82.4% and 79.3% as compared with CK, respectively. Therefore, the results showed that a combined application of 50 μmol L IAA and 2.5 mmol kg OA could effectively enhance S. alfredii Hance phytoremediation of Cd and Pb co-contaminated soil.
外源施用植物生长促进物质与螯合剂相结合是提高植物重金属提取效率的常用方法。本盆栽试验通过施用吲哚乙酸（IAA）/赤霉素（GA）单一或与草酸（OA）混合，研究了其对超积累植物垂盆草生长、生理响应和养分含量的影响，以及对镉（Cd）和铅（Pb）的植物提取效率的影响。结果表明，叶面喷施 IAA/GA 单一或与 OA 混合均可促进植物生长。与对照处理（CK）相比，50μmol L IAA 与 2.5mmol kg OA（50I+2.5OA）处理的地上部生物量最大增加 29.7%。IAA 和 GA 的存在增加了叶片中叶绿素 a、类胡萝卜素和钾的含量，降低了丙二醛的含量。50I+2.5OA 处理后叶片 Cd 含量和转运因子（TF）值分别增加了 4.29%和 21.4%，施用 50μmol L GA 与 2.5mmol kg OA 后茎和枝中 Pb 含量和 Pb 的 TF 值分别增加了 32.5%、13.4%和 57.6%，与 CK 相比。与 CK 相比，50I+2.5OA 处理的 Cd 和 Pb 最佳植物提取效率分别增加了 82.4%和 79.3%。因此，结果表明，50μmol L IAA 和 2.5mmol kg OA 的联合应用可有效增强垂盆草对 Cd 和 Pb 复合污染土壤的修复能力。
