Tea plants (Camellia sinensis O. Kuntze) can hyperaccumulate fluoride (F) in leaves. Although, aluminum (Al) can alleviate F toxicity in C. sinensis, the mechanisms driving this process remain unclear. Here, we measured root length, root activity, soluble proteins content, and levels of peroxidase, superoxide dismutase, catalase, malondialdehyde (MDA), and chlorophyll in tea leaves after treatment with different F concentrations. In addition, we focused on the content of organic acids, the gene transcription of malate dehydrogenase (MDH), glycolate oxidase (GO) and citrate synthase (CS) and the relative enzyme activity involved in the tolerance to F in C. sinensis. We also examined the role of Al in this process by analyzing the content of these physiological indicators in tea leaves treated with F and Al. Our results demonstrate that increased MDA content, together with decreased chlorophyll content and soluble proteins are responsible for oxidative damage and metabolism inhibition at high F concentration. Moreover, increased antioxidant enzymes activity regulates ROS damage to protect tea leaves during F stress. Furthermore, exogenous Al alleviated F stress in tea leaves through the regulation of MDA content and antioxidant enzymes activity. In addition, organic acids in exudate stimulated root growth in tea plants exposed to low F concentrations are regulated by MDH, GO, and CS. In addition, Al can stimulate the exudation of organic acids, and may participate in regulating rhizosphere pH of the roots through the interaction with F, eventually leading to the response to F stress in C. sinensis.

中文翻译：

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铝通过刺激茶花中有机酸的产生来缓解氟化物胁迫。

茶树（山茶）可以使叶片中的氟（F）过度积累。尽管铝（Al）可以减轻中华梭菌的F毒性，但驱动该过程的机制仍不清楚。在这里，我们测量了用不同的F浓度处理后茶叶中的根长，根活性，可溶性蛋白含量以及过氧化物酶，超氧化物歧化酶，过氧化氢酶，丙二醛（MDA）和叶绿素的水平。此外，我们集中于有机酸的含量，苹果酸脱氢酶（MDH），乙醇酸氧化酶e（GO）和柠檬酸合酶（CS）的基因转录以及涉及中华绒螯蟹对F的耐受性的相对酶活性。。通过分析用F和Al处理的茶叶中这些生理指标的含量，我们还检查了Al在此过程中的作用。我们的结果表明，高F浓度下MDA含量增加，叶绿素含量和可溶性蛋白含量降低是氧化损伤和代谢抑制的原因。此外，增加的抗氧化酶活性可调节ROS损伤，从而在F胁迫下保护茶叶。此外，外源Al通过调节MDA含量和抗氧化酶活性减轻了茶叶中的F胁迫。另外，暴露于低F浓度的茶树中渗出液刺激根部生长的有机酸受MDH，GO和CS的调节。此外，铝会刺激有机酸的渗出，山茶。