Cadmium (Cd) contamination of croplands has become a threat to crop food safety and human health. In this study, we investigated the effect of sulfur on the growth of water spinach under Cd stress and the amount of Cd accumulation by increasing the soil sulfate content. We found that the biomass of water spinach significantly increased after the application of sulfur while the shoot Cd concentration was considerably reduced (by 31%). The results revealed that sulfur could promote the expression of PME and LAC genes, accompanied by an increase in PME activity and lignin content. Also, the cell wall Cd content of water spinach roots was significantly increased under sulfur treatment. This finding suggests that sulfur could enhance the adsorption capacity of Cd by promoting the generation of cell wall components, thereby inhibiting the transportation of Cd via the apoplastic pathway. In addition, the higher expression of Nramp5 under the Cd1S0 (concentration of Cd and sulfur are 2.58 and 101.31 mg/kg respectively) treatment led to increased Cd uptake. The CAX3 and ABC transporters and GST were expressed at higher levels along with a higher cysteine content and GSH/GSSR value under Cd1S1 (concentration of Cd and sulfur are 2.60 and 198.36 mg/kg respectively) treatment, which contribute to the Cd detoxification and promotion of Cd compartmentalization in root vacuoles, thereby reducing the translocation of Cd to the shoot via the symplastic pathway.

农田的镉 (Cd) 污染已成为对作物食品安全和人类健康的威胁。在这项研究中，我们通过增加土壤硫酸盐含量来研究硫对 Cd 胁迫下菠菜的生长和 Cd 积累量的影响。我们发现，施硫后，菠菜的生物量显着增加，而地上部镉浓度显着降低（降低了 31%）。结果表明硫可以促进PME和LAC的表达基因，伴随着 PME 活性和木质素含量的增加。此外，在硫处理下，菠菜根的细胞壁镉含量显着增加。这一发现表明硫可以通过促进细胞壁成分的生成来增强对 Cd 的吸附能力，从而抑制 Cd 通过质外体途径的运输。此外，表达更高Nramp5的Cd1S0下（Cd和硫的浓度是2.58和101.31毫克/千克分别地）处理导致增加的CD摄取。该CAX3和ABC转运和GST 在 Cd1S1（Cd 和硫的浓度分别为 2.60 和 198.36 mg/kg）处理下以更高的水平表达以及更高的半胱氨酸含量和 GSH/GSSR 值，这有助于 Cd 解毒和促进根液泡中的 Cd 区室化，从而减少 Cd 通过共生途径向枝条的易位。