College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
Sci Total Environ. 2021 Mar 10;759:143501. doi: 10.1016/j.scitotenv.2020.143501. Epub 2020 Nov 11.
Exogenous silicon has been shown to enhance plant growth and alleviate heavy metals toxicity, but the regulation mechanism of silicon on cadmium migration and transformation in the soil-rice system is still unclear, which is worth further study. In this study, a pot experiment was carried out to explore the influence of different doses (0, 1 and 5%) of mineral silicon on soil properties, nutrient availability, rice growth, soil enzyme activities, Cd bioavailability, and uptake and accumulation of Cd in high-accumulating (H) and low-accumulating (L) rice cultivars grown in contaminated soils. Results showed that mineral-Si treatment could increase the total biomass and grain yield, with an increased rate of 17.7-27.3% and 14.7-19.1% for H; while 26.2-33.4% and 21.3-30.3% for L. Compared with non-mineral-Si treatment, the soil EX-Cd decreased by 3.9-13.3% (H) and 2.3-10.7% (L). Additionally, the Cd content in rice grain was significantly declined by 29.5-31.3% (H) and 34.9-35.2% (L). Mineral-Si enhanced urease, sucrase, and neutral phosphatase activities in both cultivars, but suppressed catalase activity in H. A selective change in bacterial community structure was observed under mineral-Si treatment, however, the bacterial community remained stable, suggesting that the mineral-Si had no adverse effect on the microbial community. The positive response of soil enzymes activities, rice growth and the overall stabilization of microbial environment for mineral-Si addition to the Cd contaminated soils indicated that mineral-Si could mitigate the risk of Cd and well maintain the soil health, proving it to be eco-friendly and low-cost amendment for soils remediation.
外源硅已被证明可以促进植物生长和减轻重金属毒性，但硅对土壤-水稻系统中镉迁移和转化的调节机制仍不清楚，值得进一步研究。本研究采用盆栽试验，探讨了不同剂量（0、1 和 5%）的矿物硅对受污染土壤中高积累（H）和低积累（L）水稻品种生长、土壤酶活性、镉生物有效性、吸收和积累的影响。结果表明，矿物-Si 处理可增加总生物量和籽粒产量，H 分别增加 17.7-27.3%和 14.7-19.1%，L 分别增加 26.2-33.4%和 21.3-30.3%。与非矿物-Si 处理相比，土壤有效态镉减少了 3.9-13.3%（H）和 2.3-10.7%（L）。此外，水稻籽粒中镉含量分别降低了 29.5-31.3%（H）和 34.9-35.2%（L）。矿物-Si 增强了两种水稻品种的脲酶、蔗糖酶和中性磷酸酶活性，但抑制了 H 的过氧化氢酶活性。矿物-Si 处理下观察到细菌群落结构的选择性变化，但细菌群落保持稳定，表明矿物-Si 对微生物群落没有不良影响。土壤酶活性、水稻生长和微生物环境的整体稳定对矿物-Si 添加到 Cd 污染土壤的积极响应表明，矿物-Si 可以降低 Cd 的风险，并很好地维持土壤健康，证明它是一种环保且低成本的土壤修复改良剂。
