镉、铅在沉水植物龙须眼子菜叶片中的分布

采用室内浸提、扫描电镜附加能谱分析、差数离心和凝胶层析等手段,研究了镉、铅在龙须眼子菜(Potamogeton pectinatus)叶片中的分布.结果表明,龙须眼子菜对镉、铅具有很强的吸收能力,对溶液中镉、铅的平均去除效率分别为84%、91%.当镉、铅处理液浓度分别为6.67,83.00μmol/L时,龙须眼子菜对镉、铅的生物积累量分别为496,10800mg/kg,其中可溶态镉、铅的浓度分别为55.0,14.1mg/kg,说明龙须眼子菜叶片中的镉、铅大部分都是以结合态存在的.铅在龙须眼子菜叶细胞上的分布重量百分比及原子百分比均高于镉.15%的镉和25%的铅分布在龙须眼子菜的细胞壁中;56%的镉和25%的铅分布在液泡和胞基质中.龙须眼子菜叶片中除了有小分子蛋白与镉结合外,还有其他小分子有机物也能与镉结合,而铅则主要与小分子蛋白结合.

Distribution of Cd and Pb in a submerged aquatic plant Potamogeton pectinatus

Biosorption of metals by P. pectinatus in a laboratory experiment was carried out to investigate the abilities of P. pectinatus to remove Cd and Pb from contaminated water. P. pectinatus was capable of removing large amount of Cd and Pb from solution.The average removal efficiencies were 84% and 91% for Cd and Pb, respectively. Under 6.67umolCd/L and 83.00 祄olPb/L treatment, the maximum accumulation capacities were 496 mg/kg for Cd and 10800 mg/kg for Pb and the water-soluble Cd and Pb concentrations were 55.0 and 14.1 mg/kg, respectively. Most of Cd and Pb in the aquatic plant P. pectinatus could be compositions. Scanning electron microscopic and energy-dispersive X-ray microelemental analyses revealed that there was more Pb distribution in the cell wall than Cd. The subcelluar Cd distribution in leaf cells of P. pectinatus showed that there was 15%Cd and 25% Pb distribution in the cell-wall and 56%Cd and 25%Pb distribution in soluble fraction. In this study size exclusion chromatography using a Sehadex G-50 column was also performed to separate various Cd and Pb protein complexes in short term exposure to Cd and Pb. In the leaf of P. pectinatus a portion of Cd and most of Pb binds with high molecular weight complexes, and another portion of Cd could bind with low molecular weight complexes; distribution