Bao Qiongli, Bao Wankui, Li Yan, Zhang Shengnan, Lian Fei, Huang Yizong
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjing, 300191, China.
Institute of Agricultural Resource and Regional Planning, China Academy of Agricultural Sciences, Beijing, 100081, China.
J Environ Manage. 2021 Jun 1;287:112343. doi: 10.1016/j.jenvman.2021.112343. Epub 2021 Mar 18.
Potentially toxic elements (PTE) toxicity has serious effects for human health. Si has been tested to investigate their ability to mitigate Cd and As contamination of rice. In this study, the combined effect of Si and melatonin (MT) on Cd and As uptake and transport in rice plants is tested in two contaminated soils via controlled pot experiments. Results showed that a combined Si and MT treatment (Si + MT) was more effective at reducing Cd and As uptake and transport than Si alone. The treatment had the strongest effect on Cd concentrations in rice grains from high-polluted soil (HP) when treated at the flowering stage (81.8% reduction) and from low-polluted soil (LP) at the tillering stage (TS, 64.9%). The greatest reduction of grain As was found when treated at TS in both soils, by 58.2% and 39.2% in HP and LP soil, respectively. The significant upregulation of CAT, SOD, and POD activities, and downregulation of MDA by Si + MT was more effective than that of Si alone; Si + MT significantly decreased expressions of Nramp1, HMA2, and IRT2 in roots in both soils, and also Nramp5, HMA3, and IRT1 in LP soil, which might result in Si+MT effect on Cd and As accumulation. However, Si + MT had little effect on the amino acid content of grains compared to Si alone. Overall, the combination of Si and MT was substantially more effective at reducing Cd and As uptake and transport than Si alone, especially in HP soil. This effect might result from the regulation of antioxidant potential and gene expression relating Cd uptake and transport.
潜在有毒元素（PTE）毒性对人类健康有严重影响。已对硅进行测试，以研究其减轻水稻镉和砷污染的能力。在本研究中，通过控制盆栽试验在两种受污染土壤中测试了硅和褪黑素（MT）对水稻植株中镉和砷吸收与转运的联合效应。结果表明，硅和MT联合处理（Si + MT）在减少镉和砷吸收与转运方面比单独使用硅更有效。该处理对高污染土壤（HP）开花期处理的水稻籽粒镉浓度影响最大（降低81.8%），对低污染土壤（LP）分蘖期（TS）处理的水稻籽粒镉浓度影响最大（降低64.9%）。在两种土壤的分蘖期处理时，籽粒砷的降幅最大，HP土壤和LP土壤分别降低58.2%和39.2%。Si + MT使CAT、SOD和POD活性显著上调，MDA下调，其效果比单独使用硅更显著；Si + MT显著降低了两种土壤中根中Nramp1、HMA2和IRT2的表达，以及LP土壤中Nramp5、HMA3和IRT1的表达，这可能导致Si + MT对镉和砷积累产生影响。然而，与单独使用硅相比，Si + MT对籽粒氨基酸含量影响较小。总体而言，硅和MT联合使用在减少镉和砷吸收与转运方面比单独使用硅更有效，尤其是在HP土壤中。这种效果可能源于对抗氧化潜力以及与镉吸收和转运相关的基因表达的调节。
