EFFECTS OF INORGANIC AND ORGANIC SELENIUM ON THE REGULATION OF FLUORESCENCE PARAMETERS, THIOL METABOLISM, AND SUBCELLULAR DISTRIBUTION IN RADISH UNDER ARSENIC STRESS

Arsenic (As) contamination presents a significant risk to soil quality and the safety of agricultural produce.Selenium (Se), as a helpful element, has demonstrated potential in mitigating detrimental metal stress.The distinct properties of inorganic and organic Se in mitigating As -induced stress remain ambiguous.This study performed a pot experiment to compare and examine the fluorescence characteristics, thiol metabolism, and subcellular localization of radish subjected to inorganic and organic Se treatments.The findings indicated that the Fv/Fm, Y (II), and Y (qP) values in the inorganic and organic Se treatment groups were markedly higher than those in the control group (CK) (P < 0.05).In both inorganic and organic Se groups, the content of glutathione (GSH), phytochelatins (PCs), and cysteine (Cys) at treatment levels of 3 mg Se kg -1 , 6 mg Se kg -1 , and 12 mg Se kg -1 were considerably elevated compared to the CK (P < 0.05).The As content in the cell wall was the greatest, comprising 39.9-45.7% of the total As content in the subcellular components.This work demonstrates that moderate levels of inorganic and organic Se can enhance photosynthesis, control thiol metabolism, and influence the subcellular localization of radish to mitigate As poisoning.Excessive inorganic selenium produced stress on radish.Organic Se exhibits a significant advantage in mitigating As-induced stress in radishes.This study presents a novel perspective for a comprehensive knowledge of the role of Se in heavy metal stress and proposes new strategies for plant remediation of As-contaminated soil.