Li Wei, He Si-Xue, Zhou Qian-Yu, Dai Zhi-Hua, Liu Chen-Jing, Xiao Shu-Fen, Deng Song-Ge, Ma Lena Q
Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
School of Ecology and Environment, Anhui Normal University, Wuhu, Anhui 241000, China.
J Hazard Mater. 2024 Sep 5;476:135154. doi: 10.1016/j.jhazmat.2024.135154. Epub 2024 Jul 8.
It is known that selenium (Se) enhances plant growth and arsenic (As) accumulation in As-hyperaccumulator Pteris vittata, but the associated mechanisms are unclear. In this study, P. vittata was exposed to 50 μM arsenate (AsV) under hydroponics plus 25 or 50 μM foliar selenate. After 3-weeks of growth, the plant biomass, As and Se contents, As speciation, malondialdehyde (MDA) and glutathione (GSH and GSSG) levels, and important genes related to As-metabolism in P. vittata were determined. Foliar-Se increased plant biomass by 17 - 30 %, possibly due to 9.1 - 19 % reduction in MDA content compared to the As control. Further, foliar-Se enhanced the As contents by 1.9-3.5 folds and increased arsenite (AsIII) contents by 64 - 136 % in the fronds. The increased AsV reduction to AsIII was attributed to 60 - 131 % increase in glutathione peroxidase activity, which mediates GSH oxidation to GSSG (8.8 -29 % increase) in the fronds. Further, foliar-Se increased the expression of AsIII antiporters PvACR3;1-3;3 by 1.6 - 2.1 folds but had no impact on phosphate transporters PvPht1 or arsenate reductases PvHAC1/2. Our results indicate that foliar-Se effectively enhances plant growth and arsenic accumulation by promoting the GSH-GSSG cycle and upregulating gene expression of AsIII antiporters, which are responsible for AsIII translocation from the roots to fronds and AsIII sequestration into the fronds. The data indicate that foliar-Se can effectively improve phytoremediation efficiency of P. vittata in As-contaminated soils.
已知硒（Se）能促进砷超富集植物蜈蚣草的生长和砷（As）积累，但其相关机制尚不清楚。在本研究中，水培条件下，将蜈蚣草暴露于50 μM砷酸盐（AsV）中，并叶面喷施25或50 μM硒酸盐。生长3周后，测定了植株生物量、As和Se含量、As形态、丙二醛（MDA）和谷胱甘肽（GSH和GSSG）水平以及蜈蚣草中与As代谢相关的重要基因。叶面施硒使植株生物量增加了17%-30%，这可能是由于与As对照相比，MDA含量降低了9.1%-19%。此外，叶面施硒使叶片中As含量提高了1.9-3.5倍，亚砷酸盐（AsIII）含量增加了64%-136%。AsV还原为AsIII的增加归因于谷胱甘肽过氧化物酶活性提高了60%-131%，该酶介导叶片中GSH氧化为GSSG（增加了8.8%-29%）。此外，叶面施硒使AsIII转运蛋白PvACR3;1-3;3的表达增加了1.6-2.1倍，但对磷酸盐转运蛋白PvPht1或砷酸盐还原酶PvHAC1/2没有影响。我们的结果表明，叶面施硒通过促进GSH-GSSG循环和上调AsIII转运蛋白的基因表达，有效地促进了植物生长和砷积累，这些转运蛋白负责将AsIII从根部转运到叶片并将AsIII螯合到叶片中。数据表明，叶面施硒可以有效提高蜈蚣草对As污染土壤的植物修复效率。
