Reactive oxygen species (ROS) originate as a natural byproduct in standard metabolism of oxygen activities. The principal sites of ROS generation in the cell are apoplast, mitochondria, chloroplasts, and peroxisomes. These ROS can induce cellular injuries by proteins oxidation, lipid peroxidation, and DNA damage, which finally may result in plant cellular death. Under regular circumstances, there is a steadiness between generation and elimination of ROS, but this balance is hampered by different biotic and abiotic stress factors such as exposure to heavy metals, high and low-light conditions, pathogens, insects and temperature extremes, resulting in a high generation of ROS which should be counteracted by the antioxidant machinery in cells. The antioxidant system of defense is composed by two groups: (i) Enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), general peroxidases (PRX) (e.g. guaiacol peroxidase GPX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR); (ii) Non-enzymatic antioxidants such as ascorbic acid (AA), reduced glutathione (GSH), α-tocopherol, carotenoids, plastoquinone/ubiquinone and flavonoids. These two groups of metabolites and enzymes work together with the main aim of ROS scavenging, but also in determining plant signaling, immune response, and plant growth and development. Finally, the molecular genetics of ROS genes and related metabolic pathways are briefly outlined, including gene isoforms, cellular localization, detection methods used and interactions amongst them. This information is crucial in better understanding and designing procedures for plants´stress tolerance; leading to a better management of agricultural plants under challenging and changing climatic conditions and food security.

中文翻译：

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不利环境条件下的氧化应激和抗氧化代谢：综述

活性氧 (ROS) 起源于氧活动的标准代谢中的天然副产品。细胞中产生 ROS 的主要部位是质外体、线粒体、叶绿体和过氧化物酶体。这些 ROS 可通过蛋白质氧化、脂质过氧化和 DNA 损伤诱导细胞损伤，最终可能导致植物细胞死亡。在正常情况下，ROS 的产生和消除是稳定的，但这种平衡受到不同的生物和非生物胁迫因素的阻碍，例如暴露于重金属、高光和低光条件、病原体、昆虫和极端温度，导致大量 ROS 应被细胞中的抗氧化机制抵消。防御的抗氧化系统由两组组成：(i) 酶促抗氧化剂，例如超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、抗坏血酸过氧化物酶 (APX)、一般过氧化物酶 (PRX)（例如愈创木酚过氧化物酶 GPX）、谷胱甘肽还原酶 (GR)、单脱氢抗坏血酸还原酶 (MDHAR) 和脱氢抗坏血酸还原酶（DHAR）；(ii) 非酶抗氧化剂，例如抗坏血酸 (AA)、还原型谷胱甘肽 (GSH)、α-生育酚、类胡萝卜素、质体醌/泛醌和类黄酮。这两组代谢物和酶协同工作，主要目的是清除 ROS，但也决定植物信号、免疫反应和植物生长发育。最后，简要概述了 ROS 基因的分子遗传学和相关代谢途径，包括基因亚型、细胞定位、使用的检测方法和它们之间的相互作用。这些信息对于更好地理解和设计植物胁迫耐受性程序至关重要；导致在充满挑战和不断变化的气候条件和粮食安全下更好地管理农业植物。