Glufosinate targets glutamine synthetase (GS), but its fast herbicidal action is triggered by reactive oxygen species (ROS). The relationship between GS inhibition and ROS accumulation was investigated in Amaranthus palmeri. Glufosinate's fast action is light-dependent with no visual symptoms or ROS formation in the dark. Inhibition of GS leads to accumulation of ammonia and metabolites of the photorespiration pathway, such as glycolate and glyoxylate, as well as depletion of other intermediates such as glycine, serine, hydroxypyruvate, and glycerate. Exogenous supply of glycolate to glufosinate-treated plants enhanced herbicidal activity and dramatically increased hydrogen peroxide accumulation (possibly from peroxisomal glycolate oxidase activity). Glufosinate affected the balance between ROS generation and scavenging. The activity of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase increased after glufosinate treatment in an attempt to quench the nascent ROS burst. Low doses of atrazine and dinoseb were used to investigate the sources of ROS by manipulating photosynthetic electron transport and oxygen (O2) evolution. ROS formation depended on electron flow and O2 evolution in photosystem II (PSII). Inhibition of GS disrupted photorespiration, carbon assimilation, and linear electron flow in the light reactions. Consequently, the antioxidant machinery and the water-water cycle are overwhelmed in the presence of light and glufosinate. The O2 generated by the splitting of water in PSII becomes the acceptor of electrons, generating ROS. The cascade of events leads to lipid peroxidation and forms the basis for the fast action of glufosinate.

中文翻译：

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草铵膦作用方式的新颖见解：如何形成活性氧。

草铵膦靶向谷氨酰胺合成酶（GS），但其快速除草作用是由活性氧（ROS）触发的。研究了inhibition菜中GS抑制与ROS积累的关系。草铵膦的快速作用是光依赖性的，在黑暗中没有视觉症状或ROS的形成。抑制GS会导致氨和光呼吸途径的代谢产物（例如乙醇酸和乙醛酸酯）的积累，以及其他中间体（例如甘氨酸，丝氨酸，羟基丙酮酸和甘油酸酯）的消耗。向草铵膦处理过的植物中外源供应乙醇酸酯可增强除草活性，并显着增加过氧化氢的积累（可能来自过氧化物酶体乙醇酸酯氧化酶的活性）。草铵膦影响了ROS产生和清除之间的平衡。草铵膦处理后，超氧化物歧化酶，过氧化氢酶，抗坏血酸过氧化物酶和谷胱甘肽还原酶的活性增加，试图抑制新生的ROS爆发。低剂量的阿特拉津和地洛糖被用于通过操纵光合电子传递和氧气（O2）的释放来研究ROS的来源。ROS的形成取决于光系统II（PSII）中的电子流动和氧气的释放。GS的抑制破坏了光反应中的光呼吸，碳同化和线性电子流。因此，在轻质和草铵膦的存在下，抗氧化剂机理和水-水循环不堪重负。由PSII中的水分解产生的O2成为电子的受体，从而产生ROS。