Foliar application of selenium nanoparticles (SeNPs) has been used to enhance Se concentration in winter wheat, but soil application of SeNPs on Se uptake in the crop and their transformation in soil are still limited. This study investigated the effects of varying sizes (50, 100, 200 nm) and concentrations (0, 2, 5, 25, 100 mg kg⁻¹) of chemical synthesized SeNPs in soil on uptake and accumulation of Se in the crop at maturity and related mechanisms. SeNPs not only posed very low toxic to plant growth, except for leaf, but also significantly enhanced grain Se concentration. Regardless of concentration of SeNPs added to soil, the transformation rate of the larger sized SeNPs (200 nm) in soil was significantly (p < 0.05) higher than that of the smaller one, which is mainly due to the latter was more easily adsorbed onto soil organic matter and reluctant to be oxidized. Significantly higher grain Se concentration under the larger sized SeNPs contributed to significantly higher transformation rate of SeNPs and concentration of available Se in soil. The present study showed that the larger sized SeNPs in soil had significant advantages including higher grain Se concentration and Se utilization efficiency for wheat Se biofortification.

叶面喷施硒纳米粒子 (SeNPs) 已被用于提高冬小麦中硒的浓度，但土壤施用硒纳米粒子对作物对硒的吸收及其在土壤中的转化仍然有限。本研究调查了土壤中化学合成的 SeNPs的不同尺寸（50、100、200 nm）和浓度（0、2、5、25、100 mg kg ^-1 ）对成熟时作物吸收和积累硒的影响及相关机制。SeNPs不仅对除叶片以外的植物生长具有极低的毒性，而且显着提高了籽粒硒浓度。无论添加到土壤中的 SeNPs 浓度如何，土壤中较大尺寸的 SeNPs (200 nm) 的转化率显着 ( p < 0.05) 高于较小的，这主要是由于后者更容易被土壤有机质吸附，不易被氧化。在较大尺寸的SeNPs下显着较高的谷物硒浓度有助于显着提高SeNPs的转化率和土壤中有效硒的浓度。本研究表明，土壤中较大尺寸的SeNPs具有显着优势，包括较高的籽粒硒浓度和硒利用效率，可用于小麦硒的生物强化。