镉在3种乔木中的积累及其亚细胞分布和化学形态研究

研究不同镉(Cd)浓度(0、25、50、100、200 mg·kg-1)处理下,栾树(Koelreuteria paniculata)、臭椿(Ailanthus altissima)、银杏(Ginkgo biloba)3种乔木叶、枝、根中Cd的含量与积累特征,并分析Cd对其叶片超微结构的影响,探讨Cd在3种乔木叶片与根...

Accumulation, subcellular distribution and chemical forms of cadmium in three tree species

The concentration and accumulation of Cd in leaves, stems, and roots of Koelreuteria paniculata, Ailanthus altissima, and Ginkgo biloba were studied under different treatment levels of Cadmium(Cd) concentrations(0,25,50,100,200 mg·kg^-1). The influence of Cd on the ultrastructure in leaves was further analyzed. The subcellular distribution and chemical forms of Cd in leaves and roots of the three tree species were discussed. The results showed that Cd concentration in these three species of trees increased with the increase of Cd concentration in the soil, and the accumulation was mainly in the roots. The Cd concentration in the organs of Koelreuteria paniculata and Ailanthus altissima were significantly higher than that of Ginkgo biloba,indicating that the Cd accumulation ability of Koelreuteria paniculata and Ailanthus altissima were stronger than that of Ginkgo biloba. Under the treatment of high Cd concentration, the cell structure of leaves in Koelreuteria paniculata and Ailanthus altissima was obviously damaged, with large amount of black flocs appeared in the cells and attached to cell walls and the surface of organelles. However, there was no obvious damage in the cells of leaves in Ginkgo biloba, indicating that the tolerance of Ginkgo biloba to Cd was stronger than that of Koelreuteria paniculata and Ailanthus altissima. It was also found that Cd mostly existed in the cell wall or soluble components in the leaves of the three species of trees, and Cd mostly existed in the cell wall in the root systems. Cd was less distributed in organelles such as chloroplasts, mitochondria and nucleus. HAc- and NaCl- extracted Cd had the highest distribution ratio in leaves and roots of these trees respectively, with relatively low mobility and toxicity. The accumulation ability of Cd in each organ of the trees had a significant negative correlation with the proportion of Cd in chloroplast and mitochondria components in leaf cells,and a significant positive correlation with the proportion of Cd in HAc- extracted state in leaves.