作　　者： ; ; ; ; ; ;

机构地区： 南宁师范高等专科学校

出　　处： 《农业环境科学学报》 2007年第4期1307-1311,共5页

摘　　要： 采用水培试验方法,研究了硅对镉胁迫下水稻幼苗的解毒效应及其机制。结果表明,Cd(4mg·L^(-1))处理4d后水稻幼苗出现明显的毒害症状,生物产量显著降低。然而,在镉溶液中添加30～180mg·L^(-1)SiO_2后镉毒害症状减轻,生物产量显著提高。硅处理不仅极显著减少水稻含镉量和镉的吸收量,而且减少镉累积在地上部、地下部以及在叶、茎中的比值。硅处理后细胞壁中的镉占根中镉的比例增加,而镉在共质体和质外体中的比例显著减少。硅处理还使进入根细胞自由空间的镉更多地转化为交换态,使交换态镉与游离态镉的比值升高。这些结果显示,硅通过抑制水稻对镉的吸收和镉的向上运输,而增加镉在细胞壁中的沉积和自由空间中交换态镉的比重等途径缓解镉对水稻的毒害。 The cadmium detoxification by rice（Oryza sativas L.） seedlings after the treatment with silicon and corresponding mechanisms were investigated by hydroponic culture method. The significant decrease in seedling biomass coupled with the occurrence of Cd-toxic symptoms on the rice was detected after the seedlings were exposed to 4 mg·L^-1 Cd^2＋ solution for 4 d. However, Cd toxicity was alleviated significantly by the addition of 30-180 mg·L^-1 silicon （SiO2） to cadmium solution, and the seedling biomass increased significantly. The addition of Si to Cd solution not only decreased the content of Cd in the plants and the Cd absorption by the plants, but also reduced the ratio of Cd in upper parts to that in roots, and the ratio of leaves to stems. Si increased the proportion of Cd in root cell walls but reduced the ratio of Cd in symplasts to that in apoplasts. Furthermore, the content of exchangeable Cd related to free form Cd in root cell free space （RCFS） increased after the treatment with Si, indicating that more Cd in RCFS became exchangeable after Si treatment. These results suggested that the improved Cd-resis- tance by Si would result from not only the inhibition of Cd absorption by the plants and Cd transport to the upper parts, but also the enhancement of Cd localization in cell walls and the exchangeable Cd in RCFS.

关 键 词： 硅 水稻 镉 抵御 机制

领　　域： [环境科学与工程]