Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Key Laboratory of Plant-Soil Interactions of the Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, the People's Republic of China; School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, the People's Republic of China.
Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Key Laboratory of Plant-Soil Interactions of the Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, the People's Republic of China.
J Hazard Mater. 2023 Jun 15;452:131218. doi: 10.1016/j.jhazmat.2023.131218. Epub 2023 Mar 16.
Selenium (Se) inhibits cadmium (Cd) root-to-shoot translocation and accumulation in the shoots of pak choi; however, the mechanism by which Se regulates Cd retention in roots is still poorly understood. A time-dependent hydroponic experiment was conducted to compare the effects of selenite and selenate on Cd translocation and retention in the roots. The underlying mechanisms were investigated regarding Se biotransformation and metal transportation in roots using HPLC and transcriptome analyses. Selenite showed reducing effects on Cd translocation and accumulation in shoots earlier than selenate. Selenite is mainly biotransformed into selenomethionine (80% of total Se in roots) at 72 h, while SeO was the dominant species in the selenate treatments (68% in shoots). Selenite up-regulated genes involved in the biosynthesis of lignin, suberin, and phytochelatins and those involved in stress signaling, thereby helping to retain Cd in the roots, whereas essentially, selenate had opposite effects and impaired the symplastic and apoplastic retention of Cd. These results suggest that cell-wall reinforcement and Cd retention in roots may be the key processes by which Se regulates Cd accumulation, and faster biotransformation into organic seleno-compounds could lead to earlier effects.
硒（Se）抑制镉（Cd）在小白菜根到茎中的转运和积累；然而，硒调节根中 Cd 保留的机制仍知之甚少。进行了一项时间依赖性水培实验，以比较亚硒酸盐和硒酸盐对 Cd 转运和根中保留的影响。使用 HPLC 和转录组分析研究了 Se 生物转化和金属在根中的运输对根中 Cd 保留的影响。亚硒酸盐对 Cd 向地上部的转运和积累的抑制作用早于硒酸盐。亚硒酸盐在 72 小时内主要被转化为硒代蛋氨酸（根中总 Se 的 80%），而在硒酸盐处理中，SeO 是主要的物种（地上部为 68%）。亚硒酸盐上调了参与木质素、角质和植物螯合肽生物合成以及与胁迫信号相关的基因，从而有助于将 Cd 保留在根中，而硒酸盐则具有相反的作用，并损害 Cd 的共质体和质外体保留。这些结果表明，细胞壁的增强和根中 Cd 的保留可能是 Se 调节 Cd 积累的关键过程，而更快地生物转化为有机硒化合物可能会导致更早的效果。
