National Research Center of Geoanalysis, Chinese Academy of Geological Sciences, Beijing, 100037, China; China University of Geosciences, Beijing, 100083, China.
National Research Center of Geoanalysis, Chinese Academy of Geological Sciences, Beijing, 100037, China.
Environ Pollut. 2021 Apr 1;274:116549. doi: 10.1016/j.envpol.2021.116549. Epub 2021 Jan 23.
Phytoremediation makes use of hyperaccumulating plants to remove potentially toxic elements (PTEs) from soil selectively. Most researches examining hyperaccumulators focused on how they act on a single PTE contaminant. However, there is more than one kind of PTEs in most contaminated soils. Phytoremediation approaches could be less effective in environments containing multiple PTEs contaminants. Here we examine arsenic (As) and lead (Pb) accumulation in Indian Mustard (Brassica juncea) from solutions with one or both pollutants. Indian mustard accumulates As or Pb when exposed in the single liquid exposure of As or Pb, and the highest concentrations of As and Pb in Indian Mustard reach 1,786 mg/kg and 47,200 mg/kg, respectively. But the absorption efficiencies of As and Pb decrease (by >90% for As, and ∼10-30% for Pb) when both As and Pb are present. The translocation of As and Pb from the root to leaf is also impeded by 36%-88% for As and 55-85% for Pb when treated with both PTEs. In As and Pb co-treatment, significant negative correlations between As (V) and P and between Pb and other elements (including K, Mg and Ca) were found in Indian mustard. X-ray absorption near edge (XANES) spectroscopy and subcellular extraction experiments indicate that much of the accumulated Pb bound within lead phosphate particles, and often located within the cell wall. Pb could decrease the percentage of water-soluble As and increase protein combined As in subcellular levels within Indian mustard. Based on these data, we suggest that the competition between Pb and monovalent and divalent nutrients (e.g., Ca(II), Mg(II) and K(I)), and the formation of lead phosphates within cell walls play critical roles in decreasing As and Pb co-uptake efficiencies for Indian mustard.
植物修复利用超积累植物有选择性地从土壤中去除潜在有毒元素 (PTE)。大多数研究超积累植物的研究都集中在它们对单一 PTE 污染物的作用上。然而，大多数污染土壤中不止有一种 PTE。在含有多种 PTE 污染物的环境中，植物修复方法可能效果不佳。在这里，我们研究了印度芥菜（ Brassica juncea ）从含有一种或两种污染物的溶液中对砷（As）和铅（Pb）的积累。当印度芥菜暴露在单一的砷（As）或铅（Pb）溶液中时，会积累 As 或 Pb，印度芥菜中 As 和 Pb 的最高浓度分别达到 1786 mg/kg 和 47200 mg/kg。但当同时存在 As 和 Pb 时，As 和 Pb 的吸收效率会降低（As 降低 >90%，Pb 降低约 10-30%）。As 和 Pb 从根部向叶片的转运也受到阻碍，当同时处理两种 PTE 时，As 和 Pb 的转运分别受到 36%-88%和 55-85%的阻碍。在 As 和 Pb 共处理时，在印度芥菜中发现 As (V) 和 P 之间以及 Pb 和其他元素（包括 K、Mg 和 Ca）之间存在显著的负相关。X 射线吸收近边（XANES）光谱和亚细胞提取实验表明，大部分积累的 Pb 与磷酸铅颗粒结合，通常位于细胞壁内。Pb 可以降低亚细胞水平水溶性 As 的百分比，并增加蛋白质结合 As 的百分比。基于这些数据，我们认为 Pb 与单价和二价营养物（如 Ca(II)、Mg(II) 和 K(I))之间的竞争以及细胞壁内磷酸铅的形成在降低印度芥菜中 As 和 Pb 共吸收效率方面发挥了关键作用。
