Copper-induced oxidative stress and responses of antioxidants and phytochelatins in Hydrilla verticillata (L.f.) Royle.
Copper-induced oxidative stress and responses of antioxidants and phytochelatins in Hydrilla verticillata (L.f.) Royle.
复制标题
DOI：
10.1016/j.aquatox.2006.10.006
复制
发表时间：
2006-12
影响因子：
4.5
通讯作者：
S. Srivastava;Seema Mishra-;R. D. Tripathi;S. Dwivedi;D. Gupta
中科院分区：
文献类型：
--
作者：
S. Srivastava;Seema Mishra-;R. D. Tripathi;S. Dwivedi;D. Gupta
铜虽然是必需的，但在超最佳水平下是潜在有毒的重金属，并且具有广泛的污染。研究了低浓度和高浓度铜（0.1-25μM）对水生植物黑藻Hydrilla verticillata（L.f.）Royle，为期1-7天。在25μM浓度下，植株在第7天积累了大量的铜，最大值为770μgg−1dw。生物量和光合色素在1μM浓度下变化较小，而在更高浓度下则出现显著下降。丙二醛（MDA）含量和电导率（EC）也表现出急剧增加，在较高的浓度，表明氧化胁迫。在响应铜暴露，植物表现出显着的诱导蛋白质和酶，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），但是，只有到中度曝光。总非蛋白巯基（NP-SH）和半胱氨酸水平显着增加，高达5μM的铜暴露，而在25μM，其水平急剧下降。还原型谷胱甘肽（GSH）在所有浓度下均降低，而氧化型谷胱甘肽（GSSG）同时升高。与对照相比，在第4天，在1和5μM的研究浓度下，植物螯合素（PC）也被显著诱导。然而，通过PC-SH与铜的比率描述的铜螯合作用较低（1μM时为6.5%，5μM时为2.4%），表明PC仅在铜稳态和解毒的综合机制中发挥作用。植物对中度铜暴露的耐受性和高积累潜力保证了它们对中度铜污染水体修复的适用性。
Copper, though essential, is potentially toxic heavy metal at supraoptimal level and has widespread contamination. The present investigation was carried out to study the responses induced by lower as well as higher doses of copper (0.1–25μM) in an aquatic macrophyte, Hydrilla verticillata (L.f.) Royle for a period of 1–7 days. The plants accumulated copper in high amount with a maximum of 770μgg−1dw on day 7 at 25μM. Biomass and photosynthetic pigments showed less alteration up to 1μM while at higher concentrations, significant decline occurred. Malondialdehyde (MDA) content and electrical conductivity (EC) also showed sharp increase at higher concentrations indicating oxidative stress. In response to copper exposure, plants showed significant induction of proteins and enzymes like superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT) and glutathione reductase (GR), however, only up to moderate exposures. Total non-protein thiols (NP-SH) and cysteine levels increased significantly up to 5μM copper exposure while at 25μM, their level declined drastically. Reduced glutathione (GSH) showed decrease at all concentrations while oxidized glutathione (GSSG) simultaneously increased. Phytochelatins (PCs) were also induced significantly at studied concentrations of 1 and 5μM on day 4 in comparison to control. However, copper chelation depicted by PC-SH to copper ratio was found to be low (6.5% at 1μM and 2.4% at 5μM) suggesting that PCs play only a part in integrated mechanisms of copper homeostasis and detoxification. Tolerant response of plants to moderate copper exposures and high accumulation potential warrants their suitability for remediation of moderately copper polluted water bodies.