Srivastava S, Mishra S, Tripathi R D, Dwivedi S, Trivedi P K, Tandon P K
Ecotoxicology and Bioremediation Group, National Botanical Research Institute, Rana Pratap Marg, Lucknow-226001, India.
Environ Sci Technol. 2007 Apr 15;41(8):2930-6. doi: 10.1021/es062167j.
Serious contamination of aquatic systems by arsenic (As) in different parts of the world calls for the development of an in situ cost-effective phytoremediation technology. In the present investigation, plants of Hydrilla verticillata (L.f.) Royle were exposed to various concentrations of arsenate (As(V)) (0-250 microM) and arsenite (AsIII) (0-25 microM) and analyzed for accumulation responses vis-à-vis biochemical changes. Total As accumulation was found to be higher in plants exposed to AsIII (315 microg g(-1) dw at 25 microM) compared to As(V) (205 microg g(-1) dw at 250 microM) after 7 d of treatment. Plants tolerated low concentrations of As(III) and As(V) by detoxifying the metalloid through augmented synthesis of thiols such as phytochelatins and through increased activity of antioxidant enzymes. While As(V) predominantly stimulated antioxidant enzyme activity, As(III) primarily caused enhanced levels of thiols. The maximum amount of As chelated by PCs was found to be about 39% in plants exposed to As(III) (at 10 microM) and 35% in As(V) exposed plants (at 50 microM) after 4 d. Only the respective highest concentrations of As(III) (25 microM) and As(V) (250 microM) proved toxic for normal plant growth after prolonged treatment. Thus, H. verticillata forms a promising candidate for the phytoremediation of As contaminated water.
世界不同地区的水生系统受到砷（As）的严重污染，这就需要开发一种具有成本效益的原位植物修复技术。在本研究中，黑藻（Hydrilla verticillata (L.f.) Royle）植株被暴露于不同浓度的砷酸盐（As(V)）（0 - 250微摩尔）和亚砷酸盐（AsIII）（0 - 25微摩尔）中，并针对积累反应以及生化变化进行分析。处理7天后，发现暴露于AsIII（25微摩尔时为315微克每克干重）的植株中总砷积累量高于暴露于As(V)（250微摩尔时为205微克每克干重）的植株。植物通过增强合成植物螯合肽等硫醇以及提高抗氧化酶活性来解毒类金属，从而耐受低浓度的As(III)和As(V)。As(V)主要刺激抗氧化酶活性，而As(III)主要导致硫醇水平升高。4天后，在暴露于As(III)（10微摩尔）的植株中，发现被植物螯合肽螯合的As最大量约为39%，在暴露于As(V)（50微摩尔）的植株中为35%。经过长时间处理后，仅各自最高浓度的As(III)（25微摩尔）和As(V)（250微摩尔）对正常植物生长有毒害作用。因此，黑藻是砷污染水体植物修复的一个有前景的候选植物。
