香根草对镉毒害的生理耐性和积累特性

研究了不同Cd水平(0、1、7.5、15、30mg·L-1)对香根草生理生化指标的影响.实验结果表明,香根草对Cd的积累能力与处理浓度密切相关,体内积累的Cd含量随着Cd处理浓度的增加逐渐增加.当Cd处理浓度为30mg·L-1时,根系积累的Cd含量最高达到2232mg·kg-1(以干重计).低浓度Cd(1mg·L-1和7.5mg·L-1)可促进叶绿素含量和根系活力,但随着Cd处理浓度的增加,叶绿素含量和根系活力逐渐下降.不同浓度的Cd胁迫增加了植物体内丙二醛(MDA)含量、过氧化物酶(POD)和过氧化氢酶(CAT)活性.可溶性蛋白质含量随着Cd处理浓度的增加逐渐下降.香根草对Cd的积累能力很高且主要分布在根部,但将Cd运输到地上部的能力较差.香根草虽不是Cd超积累植物,但具有比较强的稳定化能力,在污染土壤的修复方面有一定应用潜力.

Cadmium tolerance and accumulation characteristics of Vetiveria zizanioides

The present experiment was carried out to study the physiological response of Vetiveria zizanioides to different concentrations of Cd (0,1, 7.5, 15 and 30·mg L-1). The plants accumulated large amounts of Cd, up to a maximum of 2232 mg·kg-1 (DW) on day 15 when the plant was treated with 30 mg·L-1 Cd. The accumulation of Cd increased in a concentration dependent manner with more Cd being accumulated in the root. The results showed that exposure to lower Cd levels (1 and 7.5 mg·L-1) led to increased chlorophyll contents and root activities, while higher level of Cd treatment caused a significant decrease in these parameters. Malondialdehyde (MDA) contents, activities of catalase (CAT) and peroxidase (POD) were found to be significantly enhanced at all Cd concentrations. Significant decrease in the protein contents were recorded in cadmium treated roots and leaves. Cd concentrations in vetiver grass were positively correlated with Cd concentration in the solution. Most of the Cd taken up by vetiver accumulated in the roots and only a minor amount of Cd was translocated to shoots. The results suggest a great potential in using this plant in phytostabilization although vetiver is not a hyper-accumulator.