紫鸭跖草细胞中铜的分配和化学形态特征研究

目的]为从Cu在组织细胞中的分配特征和结合形态的角度揭示紫鸭跖草超积累Cu的机理。方法]利用差速离心技术研究Cu在紫鸭跖草中的亚细胞分配特征,并运用化学试剂顺序提取法和酶解法研究Cu在紫鸭跖草根和叶中的赋存形态。结果]根部Cu的分布位点主要是细胞壁,占根部全Cu的1/3以上;而叶部以叶绿体中的Cu占叶片全Cu的比例较大,约为1/4。在高浓度Cu处理或处理时间延长的情况下,根细胞中Cu向细胞壁的分配增多,向质体中的分配减少;而叶细胞中Cu向叶绿体中的分配增多,向细胞壁的分配减少。叶片中Cu主要与氨基酸、小分子色素、蛋白质、多糖等结合;而根部Cu主要与纤维素、膜结合蛋白等细胞壁物质结合。结论]Cu在细胞内的分配和存在形态可能是紫鸭跖草超积累Cu的重要机理之一。

Study on Distribution and Chemical Characteristics of Copper in Cells of Setcreasea purpurea Boom.

Objective] The aim of this study was to reveal the mechanism of copper hyper-accumulator in Setcreasea purpurea Boom.from the angle of distribution characteristics and binding form of copper in tissue cells.Method] The subcellular distribution characteristics of copper in S.purpurea was studied by the technique of differential centrifugation,and the binding form of copper in roots and leaves of S.purpurea was also investigated by the sequential chemical extraction method and the enzymolysis method.Result] copper in roots mainly distributed in the cell wall which was accounting for one third of the total copper in roots,while copper in leaves mainly distributed in the chloroplast which was accounting for a quarter to the total copper in leaves.Under the high concentration of copper or the extended treatment duration,the translocation of copper in root cells into the cell wall increased but the translocation of copper in root cells into the plastid decreased,while the translocation of copper in leaf cells into the chloroplast increased but the translocation of copper in leaf cells into the cell wall decreased.copper in leaves was mainly combined with amino acid,small molecular polymeric pigments,protein and polysaccharide,while copper in roots was mainly combined with cell wall substances such as cellulose and membrane-bound protein.Conclusion] The distribution characteristics and binding form of copper in cells is possibly one of the dominant mechanisms for copper hyper-accumulator in S.purpurea.