School of Science, China University of Geosciences, Beijing, 100083, China.
School of Science, China University of Geosciences, Beijing, 100083, China; Key Laboratory of Ecogeochemistry, Ministry of Natural Resources, Beijing, 100037, China.
Chemosphere. 2022 Sep;302:134831. doi: 10.1016/j.chemosphere.2022.134831. Epub 2022 May 3.
Human intake of selenium (Se) mainly occurs through the food chain, and is largely dependent on the bioavailability of soil Se. Sulfur (S) and phosphorus (P) also as essential nutrients for plants, their antagonistic with Se effects on Se bioavailability should be considered. We conducted pot experiments to investigate the interaction effect on the bioavailability of Se in the soil using a sequential extraction method and diffusive gradients in thin films (DGT). The results showed that the root and shoot Se of pak choi increased at most 340%-360% with S and P application, while the Se uptake by pak choi was slightly inhibited when S and P application was 100 mg kg. With high S and P application, pak choi Se had a high bioaccumulation factor (BAF) and low translocation factor (TF), and soil Soluble-Se (SOL-Se) increased 178%-299%, which due to the competitive adsorption of S, P with Se and changes in soil pH that lead to the transformation of soil Se fractions. In addition, the available Se concentration in soil measured by the DGT (C-Se) increased by 866% with exogenous S and P application, and its source was HA-Se. However, C-Se failed to show a good linear relationship with the Se content of pak choi. The application of DGT to assess the bioavailability of Se in soils where Se is present in the steady state needs to be further explored. We discuss the effect of S and P application on the bioavailability of soil Se and provide evidence for agricultural production and rational fertilizer use on Se-rich land.
人体摄入的硒（Se）主要来自食物链，而这在很大程度上取决于土壤中硒的生物可利用性。硫（S）和磷（P）也是植物必需的营养元素，因此应该考虑它们对硒生物可利用性的拮抗作用。我们采用连续提取法和扩散梯度薄膜（DGT），通过盆栽实验研究了它们对土壤中硒生物可利用性的交互影响。结果表明，施加 S 和 P 可使小白菜的根和茎叶硒含量最多增加 340%-360%，但当 S 和 P 施加量为 100mg/kg 时，小白菜对硒的吸收略有抑制。高 S 和 P 处理下，小白菜的硒生物积累因子（BAF）较高而转移因子（TF）较低，土壤可溶态硒（SOL-Se）增加 178%-299%，这是由于 S、P 与 Se 的竞争吸附以及土壤 pH 值变化导致土壤 Se 形态转化所致。此外，DGT 测量的土壤有效态硒（C-Se）含量在外源 S 和 P 处理下增加了 866%，其来源是 HA-Se。然而，C-Se 与小白菜中硒含量之间并未呈现出良好的线性关系。需要进一步探讨 DGT 应用于评估稳定态土壤 Se 生物可利用性的效果。我们讨论了 S 和 P 施加对土壤 Se 生物可利用性的影响，为富硒土地的农业生产和合理施肥提供了依据。
