The objective of this study was to investigate the effects of simultaneous application of ferrous iron [Fe(II)] and nitrate (NO₃^–) on arsenic (As) accumulation in rice plants during the entire growth period. To this end, Fe(II) and NO₃^– were simultaneously applied to As-contaminated soil in a pot experiment conducted under climate-controlled greenhouse conditions. In comparison to the control and sole treatments with Fe(II), NO₃^–, or amorphous iron (Fe) oxides, the simultaneous application of Fe(II) and NO₃^– significantly reduced As bioavailability by enhancing As(V) immobilization in the soil and also significantly inhibited As accumulation in rice plants, especially that of iAs in the grain. The presence of Fe(II) and nitrate can decrease As releasing via inhibiting reductive dissolution of iron minerals, and the Fe(II) oxidation coupled with nitrate reduction can immobilize As via incorporating As into iron secondary minerals. Therefore, the simultaneous application of Fe(II) and NO₃^– effectively decreased As accumulation in rice plants by enhancing As oxidation/immobilization mediated by abiotic/biotic Fe redox transformation and mineralization. These findings provided new insights into the Fe/N/As biogeochemical cycles and are also important from the view of agronomic management of As toxicity and mitigation in As-contaminated paddy fields.

中文翻译：

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同时施用铁和硝酸亚铁对污染水稻田中水稻累积砷的影响

本研究的目的是调查亚铁的[Fe（II）]和硝酸同时申请的效果（NO ₃ ^- ）对水稻植物砷（As）积聚在整个生长期。为此，铁（II）和NO ₃ ^-中同时在气候控制的温室条件下进行的盆栽实验施加到作为污染土壤。相比于控制和鞋底处理以Fe（II），NO ₃ ^- ，或无定形的铁（Fe）的氧化物，Fe的同时应用（II）和NO ₃ ^-通过增强土壤中As（V）的固定化，显着降低了As的生物利用度，并且还显着抑制了水稻植物中As的积累，特别是谷物中iAs的积累。Fe（II）和硝酸盐的存在可以通过抑制铁矿物质的还原溶解而减少As的释放，Fe（II）氧化与硝酸盐还原相结合可以通过将As掺入铁次生矿物质中来固定As。因此，铁（II）和NO的同时应用₃ ^-通过增强由非生物/生物Fe氧化还原转化和矿化介导的As氧化/固定化，有效减少了水稻植物中As的积累。这些发现为Fe / N / As生物地球化学循环提供了新的见识，并且从对As污染的稻田中As毒性的农业管理和减缓的角度出发，也具有重要意义。