中文摘要：

通过营养液培养并采用差速离心技术和化学试剂逐步提取法，分析了Zn对Pb在长柔毛委陵菜（Potentilla griffithii var．velutino）的器官及其亚细胞分布和化学形态的影响．结果表明，除对照外，79％～88％的Pb富集在长柔毛委陵菜的根部，并且植物体内47％～77％和13％～45％的Pb分别分布在细胞壁和可溶组分中．虽然加Zn没有改变Ph在植物亚细胞分布中“细胞壁〉可溶组分〉细胞核和叶绿体〉线粒体”的格局，但Ph和Zn的添加都增加了Ph在细胞壁的分配比例，减少其在可溶组分的富集，即Pb和Zn的添加增强了细胞壁对Pb的固持作用．长柔毛委陵菜体内的Pb以不同化学形态存在：在对照中82％～89％的Pb以乙醇提取态和水提取态存在；而在其它处理中以盐酸提取态为最高形态，占总量的28％～60％．同时，Ph和Zn的添加导致植物中Ph的乙醇提取态和水提取态等活性较强形态的分配比例减少，促进Pb向活性较弱的结合形态转移．因此，根部滞留、细胞壁固持、可溶组分的液泡区隔化和活性较强的结合形态的减少是长柔毛委陵菜耐Pb的主要机制．

英文摘要：

The effect of Zn on tissue, subcellular distribution and chemical form of Pb in Potentilla griffithii var. velutina under hydroponic culture were studied using gradient centrifugation and sequential chemical extraction. Besides the control, other treatments showed 79% -88% , 47% ~ 77% and 13% -45% of total Pb in the plant were distributed in root, cell wall and soluble fraction, respectively. Although the addition of Zn had no influence on the overall pattern of subcellular distribution of Pb： cell wall 〉 soluble fraction 〉 karyon and chloroplast 〉 mitocbondria, the addition of Pb and Zn generally increased the percentage of Pb in the cell wall and reduced it in the soluble fraction, suggesting that cell wall binding has been strengthened. As to the chemical forms, 82% ~ 89% of total Pb existed in an ethanol- and water-extractable form in the control, whereas 28% N 60% of total Pb was in an HCl-extractable form in other treatments. The addition of Pb and Zn generally reduced the percentage of ethanol- and water-extractable Pb, meaning the chemical form of Ph was transferred from relatively active forms to less active forms. In conclusion retention in root, binding to cell wall, vacuolar compartmentalization in the soluble fraction and conversion of Pb to a less active chemical form were the main tolerance mechanisms for Pb in P. griffithii vat. velutina.