National Botanical Research Institute (Council of Scientific and Industrial Research), Rana Pratap Marg, Lucknow 226 001, Uttar Pradesh, India.
Bioresour Technol. 2010 May;101(9):3025-32. doi: 10.1016/j.biortech.2009.12.031. Epub 2010 Jan 6.
Plants of Najas indica bioaccumulated significantly higher amounts of Pb (3554 microg g(-1) dw) when, exposed to varying concentrations of Pb(NO(3))(2).This also led to increased malondialdehyde (MDA), electrical conductivity (EC) and H(2)O(2) content. In response to this, the activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT) and glutathione reductase (GR) were elevated along with the induction of various molecular antioxidants including GSH, cysteine, ascorbic acid and proline. Further, Pb exposed plants showed significantly increased cysteine synthase and glutathione-S-transferase activity. Visible symptoms of toxicity were evident at 50 microM after 4d showing chlorosis and fragmentation of leaves with mucilaginous discharge. It seems that bioaccumulated Pb is efficiently tolerated by Najas plants through activation of antioxidant system and thiolic pathways which was evident by the increased biomass up to 10 microM Pb. Therefore, it appears that due to metal tolerance characteristics with high concentration factor these plants can find use in phytoremediation of aquatic system highly contaminated by Pb.
当菹草（Najas indica）暴露在不同浓度的硝酸铅（Pb(NO(3))(2)）中时，其体内显著地积累了更多的铅（3554 微克每克干重）。这也导致了丙二醛（MDA）、电导率（EC）和 H(2)O(2)含量的增加。为了应对这种情况，抗氧化酶的活性，如超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）、愈创木酚过氧化物酶（GPX）、过氧化氢酶（CAT）和谷胱甘肽还原酶（GR），以及各种分子抗氧化剂，如 GSH、半胱氨酸、抗坏血酸和脯氨酸，都被诱导升高。此外，暴露在铅下的植物表现出显著增加的半胱氨酸合酶和谷胱甘肽-S-转移酶活性。在 4 天之后，50μM 的 Pb 暴露下植物表现出明显的毒性症状，叶片出现黄化和碎裂，并伴有黏液分泌。菹草似乎能够通过激活抗氧化系统和硫醇途径来有效地耐受生物积累的铅，这一点可以从对 10μM Pb 下生物量的增加得到证明。因此，由于这些植物具有高浓度因子的金属耐受性特征，它们可能会被用于受 Pb 严重污染的水生系统的植物修复。
