Zhou Chuifan, Zhang Kai, Lin Jingwen, Li Ying, Chen Nailian, Zou Xianhua, Hou Xiaolong, Ma Xiangqing
a College of Forestry , Fujian Agriculture and Forestry University , Fuzhou , China.
Int J Phytoremediation. 2015;17(1-6):280-9. doi: 10.1080/15226514.2014.898021.
Experiments were conducted to examine the effects of different concentrations of Cd on the performance of the Cd accumulator Conyza canadensis. Cd accumulation in roots and leaves (roots>leaves) increased with increasing Cd concentration in soil. High Cd concentration inhibited plant growth, increased the membrane permeability of leaves, and caused a significant decline in plant height and chlorophyll [chlorophyll (Chl) a, Chl b, and total Chl] content. Leaf ultrastructural analysis of spongy mesophyllic cells revealed that excessive Cd concentrations cause adverse effects on the chloroplast and mitochondrion ultrastructures of C. canadensis. However, the activities of antioxidant enzymes, such as superoxide dismutase, catalase, peroxidase, total non-protein SH compounds, glutathione, and phytochelatin (PC) concentrations, showed an overall increase. Specifically, the increase in enzyme activities demonstrated that the antioxidant system may play an important role in eliminating or alleviating the toxicity of Cd in C. canadensis. Furthermore, results demonstrate that PC synthesis in plant cells is related to Cd concentration and that PC production levels in plants are related to the toxic effects caused by soil Cd level. These findings demonstrate the roles played by these compounds in supporting Cd tolerance in C. canadensis.
进行了实验以研究不同浓度的镉对镉积累植物小飞蓬生长性能的影响。根和叶中的镉积累量（根>叶）随着土壤中镉浓度的增加而增加。高镉浓度抑制植物生长，增加叶片的膜透性，并导致株高和叶绿素（叶绿素a、叶绿素b和总叶绿素）含量显著下降。对海绵叶肉细胞的叶片超微结构分析表明，过量的镉浓度对小飞蓬的叶绿体和线粒体超微结构产生不利影响。然而，超氧化物歧化酶、过氧化氢酶、过氧化物酶等抗氧化酶的活性、总非蛋白巯基化合物、谷胱甘肽和植物螯合肽（PC）的浓度总体上有所增加。具体而言，酶活性的增加表明抗氧化系统可能在消除或减轻镉对小飞蓬的毒性方面发挥重要作用。此外，结果表明植物细胞中PC的合成与镉浓度有关，并且植物中PC的产生水平与土壤镉水平引起的毒性效应有关。这些发现证明了这些化合物在支持小飞蓬对镉的耐受性方面所起的作用。
