Vázquez Saúl, Goldsbrough Peter, Carpena Ramón O
Department of Agricultural Chemistry, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Plant Physiol Biochem. 2009 Jan;47(1):63-7. doi: 10.1016/j.plaphy.2008.09.010. Epub 2008 Oct 8.
The biosynthesis of phytochelatins (PCs) plays a crucial role in the detoxification and homeostasis of heavy metals and metalloids in plants. However, in an increasing number of plant species metal(loid) tolerance is not well correlated with the accumulation of PCs: tolerant ecotypes frequently contain lower levels of PCs than non-tolerant ecotypes. In this study we have compared the responses of soybean (Glycine max L. cv. Resnik) and white lupin (Lupinus albus L. cv. Marta) to cadmium and arsenate in order to assess the role of homophytochelatins (hPCs) in the tolerance of soybean to these toxic elements. Soybean plants treated with Cd and As showed a high contribution of homo-glutathione (hGSH) to the pool of thiols in shoots in comparison to white lupin. Higher levels of hPCs in Cd-treated soybeans compared to PCs in lupins did not prevent growth inhibition. In contrast, the role of hPCs in the detoxification mechanism to arsenate in soybean seems to be clearer, showing higher thiol concentrations and lower growth reductions than those present in lupin plants.
植物螯合肽（PCs）的生物合成在植物对重金属和类金属的解毒及内稳态维持中起着关键作用。然而，在越来越多的植物物种中，金属（类金属）耐受性与PCs的积累并无良好的相关性：耐受性生态型所含的PCs水平通常低于非耐受性生态型。在本研究中，我们比较了大豆（Glycine max L. cv. Resnik）和白羽扇豆（Lupinus albus L. cv. Marta）对镉和砷酸盐的反应，以评估高植物螯合肽（hPCs）在大豆对这些有毒元素耐受性中的作用。与白羽扇豆相比，用镉和砷处理的大豆植株中，高谷胱甘肽（hGSH）对茎中硫醇池的贡献较大。与羽扇豆中的PCs相比，镉处理大豆中较高水平的hPCs并不能阻止生长抑制。相反，hPCs在大豆对砷酸盐的解毒机制中的作用似乎更明显，与羽扇豆植株相比，其硫醇浓度更高，生长减少更少。
