不同pH值下巯基活化硅对土壤和水稻镉含量的影响

Effect of Thiol Activated Silicon on Contents of Cadmium in Soil and Rice under Different pH Conditions

采用盆栽试验,研究了在pH值4.5、5.5、6.5条件下施用巯基活化硅对土壤Cd含量及水稻Cd累积的影响,以期为生产实践中施用巯基活化硅修复重金属污染土壤提供理论和技术依据。结果表明,在不同pH值条件下,随着巯基活化硅施用量的增加,土壤有效态Cd、水稻不同部位Cd含量均呈先减后增的趋势。施用巯基活化硅后可抑制水稻根系对土壤中Cd的富集,促进Cd从水稻根系向茎叶迁移转运,减少糙米对茎叶中Cd的积累。在pH值4.5条件下,巯基活化硅225 kg/hm^2处理土壤有效态Cd含量最低,较不施巯基活化硅处理(对照)显著降低26.0%,水稻糙米、茎叶和根系Cd含量分别显著降低45.0%、43.8%和66.8%。在pH值5.5和6.5条件下,施用巯基活化硅150 kg/hm^2处理降Cd效果最佳,土壤有效态Cd含量降低28.9%和20.9%,水稻糙米Cd含量降低29.3%和34.9%,茎叶Cd含量降低29.3%和39.4%,根系Cd含量降低60.0%和44.4%。综上,施用巯基活化硅可以有效降低土壤中有效态Cd含量,抑制水稻体内Cd向籽粒中转运,从而降低稻米Cd累积的风险。

A pot experiment was conducted to study the effects of thiol activated silicon on the soil Cd content and Cd accumulation in rice under pH values of 4.5,5.5 and 6.5 conditions,so as to provide theoretical and technical basis for the practical application of thiol activated silicon for the remediation of heavy metal contaminated soil.The results showed that under different pH values conditions,with the increase of the application amount of activated silicon in sulfhydryl group,the soil available Cd content and the contents of Cd in different parts of rice decreased first and then increased.The application of thiol activated silicon could inhibit the enrichment of Cd in soil by rice root system,promote the transfer and transport of Cd in rice roots to stem and leaves,and reduce the accumulation of Cd in the stems and leaves of brown rice.Under pH 4.5,the soil Cd content was the lowest under the treatment of 225 kg/ha thiol activated silicon,which was significantly reduced by 26.0%compared to the treatment with no thiol activated silicon(control),and the Cd contents in brown rice,stems and leaves and roots of rice were significantly reduced by 45.0.%,43.8%and 66.8%.Under pH 5.5 and 6.5,150 kg/ha thiol activated silicon had the optimum reduction effect for Cd,the soil available Cd contents decreased by 28.9%and 20.9%,the Cd contents of brown rice decreased by 29.3%and 34.9%,the contents of Cd in stem and leaf decreased by 29.3%and 39.4%,and the contents of Cd in root reduced by 60.0%and 44.4%.In conclusion,the application of thiol activated silicon could effectively reduce the available Cd contents in soil,and inhibit the Cd translocation and translocation from other parts to the grain,therefore,thiol activated silicon could be a effective way to control Cd accumulation in rice.