羊栖菜中微量金属元素的亚细胞分区分布

Subcellular distributions of trace metals in Sargassum fusiforme

运用亚细胞分级方法分析羊栖菜亚细胞组分中6种必需元素Cu、Fe、Mn、Zn、Mg、Ca以及有害元素cd、Pb、Al、As的含量，以揭示羊栖菜中不同微量元素的亚细胞分区分布特征，探讨其特异性富集砷的特性。研究结果表明，Cu、Fe、Mn、Zn、Ca、Mg等必需微量元素主要储存在细胞壁中，而在胞液和细胞器中的分布特征不同。对于Al、Cd和Pb，细胞壁中的浓度远高于细胞器和胞液，但是对于As，胞液是最主要的储存部位，分布比例约为58％，其次为细胞壁（约为26％～27％），最后为细胞器（约为15％～16％）。通过本研究推断胞液对As的区隔化作用很可能是羊栖菜特异性富集As和解毒As的重要原因。

The subcellular distributions of Cu, Fe, Mn, Zn, Mg, Ca, Cd, Pb, Al, and As in Sargassum fusiforme were examined in order to reveal the distributional characteristics of different elements and the mechanism of its special hyperaccumulation of As. The results in dicated that Cu, Fe, Mn, Zn, Ca and Mg were mainly stored in the plant cell walls, and the dis-tributional patterns in cytoplasmic supernatant and cell organelles were different. The concen trations of Al, Cd and Pb in the cell wails were much higher than those in either cytoplasmic su pernatant or cell organdies. However, the subcellular distributions of As showed a decreasing trend as： cytoplasmic supernatant （58%） 〉cell wall （26%-27%）〉cell organelles （15%-16%）, indicating that the cytoplasmic supernatant was the main storage for As in S. fusiforme. The present study suggests that the isolation of As in cytoplasmic supernatant may be an important mechanism for accumulation of As in S. fusiforme.