The tea plant [Camellia sinensis (L.) O. Kuntz] is a well-known hyper-accumulator of aluminum (Al3+) that can grow in acidic soils contaminated with excess levels of Al3+. In this work, we used various assays for ascorbate–glutathione cycle components and other antioxidant enzymes to show that the alterations in the redox status after Al3+ treatment on tea cultivars, TV23 (tolerant) and S3A1 (sensitive), is responsible for their differential tolerance to Al3+ stress. A lower dose of Al3+ stress hastened the growth rate as suggested by an increase in biomass with respect to the control in both roots and leaves, but on further increasing the dose, the reverse occurred. Organic acid exudation has a major role in Al3+ detoxification. This study also reports the involvement of oxalate as a major exudate, since the activity of glycolate oxidase (GO) was found to drastically increase under the Al3+ stress condition. The increment in reactive oxygen species production and accumulation was quantitated in terms of malondialdehyde (MDA), super oxide anion (O2−), and hydrogen peroxide (H2O2), which was followed by a rapid increase in the activity of many stress-responsive antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX). The results indicated that differential tolerance to Al3+ toxicity in tea varieties is linked to their oxidative stress response; and, antioxidant enzymes, as a crucial constituent of the defense response, appear to function differentially in the two cultivars. This is the first report showing differential tolerance of two contrasting varieties of ‘Assam Tea’ to Al3+ stress.

中文翻译：

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氧化还原状态和草酸盐渗出决定了两种不同品种的“阿萨姆茶”[Camelia sinensis (L.) O. Kuntz] 对铝毒性的耐受性差异

茶树 [Camellia sinensis (L.) O. Kuntz] 是众所周知的铝 (Al3+) 超蓄积剂，可以在被过量 Al3+ 污染的酸性土壤中生长。在这项工作中，我们对抗坏血酸 - 谷胱甘肽循环成分和其他抗氧化酶进行了各种分析，以表明在 Al3+ 处理茶品种 TV23（耐受）和 S3A1（敏感）后氧化还原状态的改变是它们差异耐受性的原因Al3+ 应力。与对照相比，根和叶中生物量的增加表明，较低剂量的 Al3+ 胁迫加速了生长速度，但在进一步增加剂量时，情况正好相反。有机酸渗出在 Al3+ 解毒中起主要作用。这项研究还报告了草酸盐作为主要渗出物的参与，因为发现乙醇酸氧化酶 (GO) 的活性在 Al3+ 胁迫条件下急剧增加。活性氧产生和积累的增加用丙二醛 (MDA)、超氧阴离子 (O2−) 和过氧化氢 (H2O2) 进行量化，随后许多应激反应性抗氧化剂的活性迅速增加酶，包括超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT) 和过氧化物酶 (POX)。结果表明，茶叶品种对Al3+毒性的差异耐受与其氧化应激反应有关；并且，抗氧化酶作为防御反应的重要组成部分，似乎在两个品种中发挥着不同的作用。这是第一份报告显示两种不同的“阿萨姆茶”品种对 Al3+ 胁迫的不同耐受性。