Zn对水稻吸收转运Cd的影响

Effects of exogenous zinc on cadmium uptake and transport in rice

通过探究锌(Zn)对水稻吸收、积累镉(Cd)的影响,为揭示水稻体内Zn、Cd互作机制提供理论依据。通过水培实验,研究Cd胁迫下施加Zn对水稻生物量、Cd含量、Cd积累量、根表铁膜成分、细胞壁组分及吸附解析动力学特征的影响。结果表明:与单Cd处理相比,Cd+Zn处理地上部生物量显著下降;根及地上部Cd含量、积累量显著提高;根表铁膜中Fe含量及Cd含量分别提高18.70%和29.99%;比较单Cd与Cd+Zn的细胞壁组分发现,Zn显著降低了水稻根细胞壁中的果胶及半纤维素1( HCl)成分,导致Cd+Zn处理细胞壁吸附能力下降而解吸能力增强。研究表明,Zn促进Cd在根表铁膜中Cd积累量,降低细胞壁的阻隔作用,进而促进水稻对Cd的吸收及转运。

To investigate the effects of exogenous Zn on Cd uptake and accumulation in rice plants, we analyzed plant biomass, cell wall components, and concentrations of Cd in root iron plaque, roots, and shoots of rice plants under Cd stress with or without addition of Zn by using a high Cd-accumulating rice variety, Yanliangyou 888. The results showed that shoot biomass of rice plants was significantly de creased under exposure to both Zn and Cd, compared with exposure to Cd only. Applied Zn significantly increased Cd accumulation in both roots and shoots of rice under Cd stress. The concentrations of Fe and Cd were also 18.70% and 29.99% higher, respectively, in root iron plaque collected from rice plants exposed to Zn relative to control plants. Meanwhile, exogenous Zn significantly reduced the contents of pectin and hemicellulose in roots, decreasing the capacity of cell walls to absorb Cd. These results suggest that Zn may increase root uptake of Cd in rice by improving Cd absorption by the iron plaque, promoting the translocation of Cd to shoots by reducing metal absorption by cell walls in roots.