Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
Ecotoxicol Environ Saf. 2010 Sep;73(6):1314-22. doi: 10.1016/j.ecoenv.2009.12.023. Epub 2010 Jan 15.
In the present study, Hydrilla verticillata plants were exposed to arsenate (AsV; 50 microM) and arsenite (AsIII; 5 microM) under variable S supply: deficient (2 microM S, -S), normal (1 mM S, +S) and excess (2 mM S, +HS). Arsenic accumulation (microg g(-1) dw) in +HS plants was about 2-fold higher upon exposure to both AsV (30) and AsIII (50) than that observed in +S (12 & 24) and -S (14 & 26) plants. Despite lower As accumulation, -S plants experienced the maximum oxidative stress owing to an inadequate response of enzymatic and molecular antioxidants and significant decline in total thiols and the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). By contrast +HS plants had significant increase in total thiols and an improved redox status, did not demonstrate any negative impact to antioxidants except catalase and hence experienced the least increase in oxidative stress parameters. In conclusion, an increase in S supply to plants may improve their accumulation capacity for As through enhanced tolerance caused by a positive effect on thiol metabolism and antioxidant status of the plants.
在本研究中，受可变硫供应条件影响，将轮藻暴露于砷酸盐（AsV；50μM）和亚砷酸盐（AsIII；5μM）中：缺硫（2μM S，-S）、正常硫（1mM S，+S）和过硫（2mM S，+HS）。与+S（12 和 24）和-S（14 和 26）植物相比，+HS 植物在暴露于两种砷酸盐（AsV 为 30，AsIII 为 50）时，砷的积累（μg g(-1) dw）约增加了 2 倍。尽管砷的积累较低，但-S 植物由于酶和分子抗氧化剂的反应不足以及总巯基和还原型谷胱甘肽（GSH）与氧化型谷胱甘肽（GSSG）的比例显著下降，经历了最大的氧化应激。相比之下，+HS 植物的总巯基显著增加，氧化还原状态得到改善，除过氧化氢酶外，抗氧化剂没有受到任何负面影响，因此氧化应激参数的增加最小。总之，增加植物的硫供应可能会通过对植物的巯基代谢和抗氧化状态产生积极影响来提高其对砷的积累能力。
