C.S.I.R. -National Botanical Research Institute, Council of Scientific and Industrial Research, Lucknow 226001, India; Department of Environmental Sciences, Babasaheb Bhimrao Ambedkar (Central) University, Rae bareily Road, Lucknow-226025, India.
C.S.I.R. -National Botanical Research Institute, Council of Scientific and Industrial Research, Lucknow 226001, India.
Ecotoxicol Environ Saf. 2012 May;79:189-198. doi: 10.1016/j.ecoenv.2011.12.019. Epub 2012 Feb 5.
The mechanism of arsenic (As) tolerance was investigated on two contrasting rice (Oryza sativa L.) genotypes, selected for As tolerance and accumulation. One tolerant (Triguna) and one sensitive (IET-4786) variety were exposed to various arsenate (0-50 μM) levels for 7 d for biochemical analyses. Arsenic induced oxidative stress was more pronounced in IET-4786 than Triguna especially in terms of reactive oxygen species, lipid peroxidation, EC and pro-oxidant enzymes (NADPH oxidase and ascorbate oxidase). However, Triguna tolerated As stress through the enhanced enzymes activities particularly pertaining to thiol metabolism such as serine acetyl transferase (SAT), cysteine synthase (CS), γ-glutamyl cysteine synthase (γ-ECS), γ-glutamyl transpeptidase (γ-GT), and glutathione-S-transferase (GST) as well as arsenate reductase (AR). Besides maintaining the ratio of redox couples GSH/GSSG and ASC/DHA, the level of phytochelatins (PCs) and phytochelatin synthase (PCS) activity were more pronounced in Triguna, in which harmonized responses of thiol metabolism was responsible for As tolerance in contrast to IET-4786 showing its susceptible nature towards As exposure.
研究了两种具有对比性的水稻（Oryza sativa L.）基因型对砷（As）的耐受机制，这两种基因型分别是对 As 有耐受和积累能力的选择品系。将一个耐受（Triguna）和一个敏感（IET-4786）品种暴露于不同浓度的砷酸盐（0-50 μM）下 7 天，进行生化分析。与 Triguna 相比，IET-4786 中砷诱导的氧化应激更为明显，特别是在活性氧、脂质过氧化、EC 和促氧化剂酶（NADPH 氧化酶和抗坏血酸氧化酶）方面。然而，Triguna 通过增强与硫醇代谢相关的酶的活性来耐受 As 胁迫，特别是丝氨酸乙酰转移酶（SAT）、半胱氨酸合酶（CS）、γ-谷氨酰半胱氨酸合酶（γ-ECS）、γ-谷氨酰转肽酶（γ-GT）和谷胱甘肽-S-转移酶（GST）以及砷酸盐还原酶（AR）。除了维持氧化还原对 GSH/GSSG 和 ASC/DHA 的比例外，Triguna 中植物螯合肽（PCs）和植物螯合肽合酶（PCS）的水平更为明显，这表明在 Triguna 中，硫醇代谢的协调反应是其耐受 As 的原因，而 IET-4786 则表现出对 As 暴露的敏感性。
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