镉、铅在玉米幼苗中的积累和迁移--X射线显微分析

用扫描电镜-X射线能谱仪及原子吸收分光光度计,测定经不同浓度镉、铅处理的玉米根、叶中镉、铅的积累。结果表明,铅的积累为皮层>中柱;木质部薄壁组织>导管。镉则相反。铅主要以非共质体途径在根内横向迁移,镉主要以共质体途径在根内横向迁移。原于吸收分光光度计测定表明,镉、铅主要在玉米根内沉积,镉铅复合作用促进了玉米根叶对镉、铅的吸收,镉比铅更易为玉米吸收且更易从根向叶迁移。

ACCUMULATION AND TRANSPORT OF CADMIUM AND LEAD IN THE SEEDLINGS OF MAIZE

After treated with different doses of Cd(2+) and Pb(2+), the contents of the metals in the roots and leaves of maize(Zea mays L.)were determined by the scanning microscopy-X ray microanalysis and the atomic absorption spectrophotometer. The results showed that there was more Cd accumulated in the seedlings of maize than Pb. The Pb contents in the cortex was more than that in the stele and in the xylem parenchyma was more than that in the vessel while Cd contents in these parts appeared to be another way around, indicating that Pb was transported mainly in the apoplast and Cd in the symplast.