镉和锌在皖景天细胞内的分布及化学形态

运用差速离心法和化学试剂逐步提取法,分析了Cd和Zn在皖景天根、茎和叶的亚细胞分布及其化学形态.结果表明:10 μmol·L^-1 Cd处理下，Cd在皖景天细胞内的主要分布位点是其可溶部分；在100 μmol·L^-1 Cd处理下，Cd在根中主要分布在细胞壁、茎中主要分布在细胞壁和可溶部分、叶中超过90%的Cd分布在可溶部分.高Cd浓度处理时，皖景天根、茎和叶的细胞壁中Cd分布比例增加，而可溶部分Cd分布比例相对减少.在1和800 μmol·L^-1 Zn处理条件下，Zn在皖景天根、茎和叶的主要分布位点是可溶部分；高Zn浓度处理时，皖景天叶、茎和根的可溶部分和细胞壁中Zn的分布比例无明显变化.细胞器中Zn和Cd分布都很少.Cd在皖景天根、茎和叶内主要以氯化钠提取态和水提取态存在，Zn在皖景天根、茎和叶内以多种化学形态存在.

Subcellular distribution and chemical forms of Cd and Zn in Sedum jinianum.

With water culture and by using differential centrifugation technique and sequential extraction, the subcellular distribution and chemical forms of Cd and Zn in the root, stem and leaf of Sedum jinianum were studied. In treatment 10 μmol Cd·L^-1, most of Cd in S. jinianum was in the soluble fraction of cell; while in treatment 100 μmol Cd·L^-1, the Cd in root was mainly deposited on cell wall, the Cd in stem was mainly on cell wall and in soluble fraction, and over 90% of Cd in leaf were in soluble fraction. In treatment 100 μmol Cd·L^-1, the proportion of Cd on the cell walls of root, stem and leaf increased, while that in soluble fraction decreased. In treatments 1 and 800 μmol Zn·L^-1, the Zn in root, stem and leaf mainly presented in soluble fraction; while in treatments with the Zn level between 1.0 and 800 μmol·L^-1, there were no differences in the proportions of Zn in the soluble fraction and on the cell walls of root, stem and leaf. Very low proportions of Cd and Zn were found in cell organelle. The Cd in the root, stem and leaf was predominated with NaCl- and water-extractable forms, while Zn in the plants were existed in numerous chemical forms.