Selenium (Se) serves as a natural detoxifier for the typical toxic heavy metal mercury (Hg), and the interactions between Se and Hg have attracted considerable scholarly attention in the field of Se and Hg. However, there is currently a lack of systematic summaries and discussions about Se–Hg interactions in soil–plant systems. This study summarizes the microscopic processes and macroscopic manifestations of Se–Hg interactions by exploring their characteristics, occurrence and mechanisms, revealing a dual-pump driving mechanism that emphasizes the “soil-root” and “atmosphere-leaf” interface of Se–Hg interactions in soil–plant systems. At the soil–root interface, HS⁻ (H₂S), Fe²⁺ and microorganisms are the key factors that cause the transformation of Se and Hg through oxidation, reduction, methylation and demethylation processes controlled by microbial or abiotic factors. Concurrently, Se reinforces the iron plaque barrier to decrease Hg absorption or to form HgSe complexes to limit Hg transportation into roots. Furthermore, the leaves, as the main plant tissue for Hg/Se uptake and bioaccumulation, are the key sites for the morphological transformation of Hg and Se, where Se–Hg interactions are likely to occur, and thus may constitute the other driving mechanism in the atmosphere–leaf interface. Finally, Se–Hg interactions are outlined after concluding the potential mechanisms, challenges and future research directions.

中文翻译：

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土壤-植物系统中硒和汞的相互作用：特征、发生和机制


硒（Se）是典型有毒重金属汞（Hg）的天然解毒剂，Se和Hg之间的相互作用在Se和Hg领域引起了学术界的广泛关注。然而，目前缺乏关于土壤-植物系统中Se-Hg相互作用的系统总结和讨论。本研究通过探究Se-Hg相互作用的特征、发生和机制，总结了Se-Hg相互作用的微观过程和宏观表现，揭示了强调Se-Hg相互作用“土壤-根”和“大气-叶”界面的双泵驱动机制在土壤-植物系统中。在土壤-根界面，HS ^- (H ₂ S)、Fe ²⁺和微生物是通过微生物或非生物因素控制的氧化、还原、甲基化和去甲基化过程引起Se和Hg转化的关键因素。同时，硒增强铁斑屏障，减少汞吸收或形成硒化汞络合物，限制汞转运到根部。此外，叶子作为Hg/Se吸收和生物富集的主要植物组织，是Hg和Se形态转化的关键部位，很可能发生Se-Hg相互作用，因此可能构成Hg和Se形态转化的另一个驱动机制。大气-叶片界面。最后，在总结潜在机制、挑战和未来研究方向后，概述了 Se-Hg 相互作用。