Diarra Ivan, Kotra Krishna Kumar, Prasad Surendra
School of Biological and Chemical Sciences, Faculty of Science, Technology and Environment, The University of the South Pacific, Laucala Campus, Suva, Fiji.
School of Biological and Chemical Sciences, Faculty of Science, Technology and Environment, The University of the South Pacific, Emalus Campus, Port Vila, Vanuatu.
Chemosphere. 2021 Jun;273:128483. doi: 10.1016/j.chemosphere.2020.128483. Epub 2020 Oct 4.
A pot incubation experiment under natural conditions was designed to investigate the effects of three biodegradable chelating agents, namely; the [S,S]-isomer of ethylenediamine disuccinate (EDDS), citric acid (CA), and tetrasodium N,N-Bis(carboxymethyl)-L-glutamate acid (GLDA), on two plant species (Brassica juncea and Brassica rapa) in terms of plant foliar growth, dry matter yield, and heavy metal (HM) accumulation. Both plant species exhibited diminished growth and symptoms of phytotoxicity under HM stress. The application of EDDS and CA affected plant foliar growth, biomass production, and led to the development of chlorotic lesions on leaves. EDDS and CA also decreased the shoot length by 38.5% and 45.2% in B. juncea, and 60.1% and 100% in B. rapa, respectively. In contrast, GLDA relieved HM stress by significantly increasing plant growth (P > 0.05) and was shown to be well tolerated (tolerance index [TI]; B. juncea = 99% and B. rapa = 123%). Among both plants, B. juncea displayed the ability to accumulate a wider range of HMs at higher concentrations. Amongst the three chelators, EDDS induced the highest bioconcentration (BCF) of Pb (2.45), Zn (2.68), and Cd (3.36) while CA achieved better results for Ni (4.01) and Cr (1.45). However, the current results showed that even with the application of chelating agents, HMs were predominantly accumulated in roots and translocation factor was generally <1. The findings of this investigation emphasize that chelate-assisted phytoextraction with Brassica spp. is highly limited in multi-metal settings, making it an unsuitable option for severely contaminated sites.
设计了一项在自然条件下的盆栽试验，以研究三种可生物降解螯合剂，即乙二胺二琥珀酸（EDDS）的[S,S] - 异构体、柠檬酸（CA）和N,N - 双（羧甲基）-L - 谷氨酸四钠（GLDA），对两种植物（芥菜和芜菁）在植物叶片生长、干物质产量和重金属（HM）积累方面的影响。在重金属胁迫下，两种植物均表现出生长受抑制和植物毒性症状。EDDS和CA的施用影响了植物叶片生长、生物量生产，并导致叶片出现褪绿病变。EDDS和CA还分别使芥菜的茎长降低了38.5%和45.2%，使芜菁的茎长降低了60.1%和100%。相比之下，GLDA通过显著促进植物生长缓解了重金属胁迫（P > 0.05），并且显示出良好的耐受性（耐受指数[TI]；芥菜 = 99%，芜菁 = 123%）。在这两种植物中，芥菜表现出在更高浓度下积累更广泛重金属的能力。在三种螯合剂中，EDDS诱导的铅（2.45）、锌（2.68）和镉（3.36）的生物富集系数（BCF）最高，而CA对镍（4.01）和铬（1.45）取得了更好的结果。然而，目前的结果表明，即使施用了螯合剂，重金属仍主要积累在根部，转运系数通常<1。本研究结果强调，在多金属环境中，用芸苔属植物进行螯合辅助植物提取的能力非常有限，使其不适用于污染严重的场地。
