Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan.
Department of Environmental Sciences and Engineering, Government College University, Allama Iqbal Road, 38000, Faisalabad, Pakistan.
Chemosphere. 2019 Jul;226:454-462. doi: 10.1016/j.chemosphere.2019.03.182. Epub 2019 Mar 31.
Food contamination with cadmium (Cd) is a serious health threat to humans worldwide and Cd accumulation by rice is a major source of Cd entrance to the food chain. Silicon (Si) application decreases the Cd content in rice but the timing of Si application may need further investigation. The present study investigated the effect of split application of Si in the soil (600 kg/ha of Si) at different growth stages of rice on the growth and Cd accumulation by rice under Cd stress. Rice plants were grown in the presence and absence of Cd and Si was applied in the soil at different growth stages of rice under Cd stress. The results indicated that Cd stress alone reduced the growth and photosynthesis and increased the Cd content in different tissues and grains of rice. Silicon application improved the plant growth and reduced the Cd accumulation, translocation factor, and bioaccumulation factor in rice especially in grains, whereas the response of Si varied with the application of Si at different growth stages. The application of Si in three splits (transplanting (S1), tillering (S2), panicle initiation (S3)) was the best in improving growth and reducing Cd concentrations in plants compared to other combinations of Si application. Silicon application in three splits (S1+S2+S3) reduced the grain Cd concentrations below the threshold level (0.2 mg/kg) and reduced the Cd health risk index under the experimental conditions. Overall, split application of Si at three growth stages may function as remediator and diminishes Cd uptake into rice grains.
食物受到镉（Cd）污染对全球人类的健康构成了严重威胁，而水稻对镉的积累是食物链中镉进入的主要来源。硅（Si）的施用可以降低水稻中的镉含量，但 Si 的施用时机可能需要进一步研究。本研究探讨了在不同生长阶段分施土壤硅（600kg/ha 的 Si）对 Cd 胁迫下水稻生长和 Cd 积累的影响。在存在和不存在 Cd 的情况下种植水稻，并在 Cd 胁迫下向土壤中不同生长阶段的水稻施 Si。结果表明，Cd 胁迫单独降低了水稻的生长和光合作用，并增加了不同组织和稻谷中 Cd 的含量。硅的施用提高了植物的生长，并降低了水稻中 Cd 的积累、迁移因子和生物累积因子，尤其是在稻谷中，而 Si 的响应随不同生长阶段 Si 的施用而变化。与其他 Si 施用组合相比，分三次（移栽（S1）、分蘖（S2）、孕穗（S3））施 Si 的效果最好。与其他 Si 施用组合相比，分三次（S1+S2+S3）施用 Si 降低了稻谷中的 Cd 浓度，使其低于阈值（0.2mg/kg），并降低了实验条件下的 Cd 健康风险指数。总的来说，在三个生长阶段分施 Si 可能作为修复剂，减少 Cd 进入水稻籽粒。
