Abstract Soil waterlogging and subsequent reoxygenation can severely impair soybean (Glycine max) growth and productivity. Here we aimed at showing the main biochemical events that occur in soybean plants during waterlogging and reoxygenation conditions. Roots and leaves were analyzed from the first hour up to ten days of waterlogging and reoxygenation imposition. During the first hours of waterlogging, reactive oxygen species (ROS) and nitric oxide (NO) accumulated in roots and leaves. In roots, only NO levels were persistent, while ROS peaked and decreased over time. In leaves, both ROS and NO increased and remain at high levels during the entire experiment. Despite the increased activity of antioxidant enzymes, malondialdehyde (MDA) levels increased and photosynthetic pigment levels declined. The NO levels increased in response to the increment in nitrate reductase activity in the roots, while in the leaves additional biosynthetic pathways seemed to be involved. The activity of fermentative enzymes and the accumulation of lactate and ethanol occurred after a few hours of waterlogging. Regarding reoxygenation, the transient increase in ROS and NO levels were again observed in roots as well as the increase in MDA levels and antioxidant enzyme activities. In leaves, the levels of ROS and NO decreased as did the activity of the antioxidant enzymes and the MDA levels. In contrast, the levels of photosynthetic pigments increased to pre-waterlogging levels. Both the activity and products of fermentative metabolism decreased. Overall, the biochemical events in soybean plants under waterlogging and reoxygenation conditions are dynamic and change during the time course of stress.

中文翻译：

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大豆植株在涝渍和复氧过程中的时程生化分析

摘要 土壤涝渍和随后的复氧会严重损害大豆（Glycine max）的生长和生产力。在这里，我们旨在展示在涝渍和再充氧条件下发生在大豆植物中的主要生化事件。从浸水和再充氧的第一个小时到十天，对根和叶进行了分析。在涝渍的最初几个小时内，根和叶中积累了活性氧 (ROS) 和一氧化氮 (NO)。在根中，只有 NO 水平持续存在，而 ROS 则随时间达到峰值并下降。在叶子中，在整个实验过程中，ROS 和 NO 都增加并保持在高水平。尽管抗氧化酶的活性增加，丙二醛 (MDA) 水平增加，光合色素水平下降。NO 水平随着根中硝酸还原酶活性的增加而增加，而在叶子中似乎涉及额外的生物合成途径。发酵酶的活性以及乳酸和乙醇的积累发生在淹水几小时后。关于复氧，在根中再次观察到 ROS 和 NO 水平的瞬时增加以及 MDA 水平和抗氧化酶活性的增加。在叶子中，ROS 和 NO 的水平降低，抗氧化酶的活性和 MDA 水平也降低。相比之下，光合色素的水平增加到淹水前的水平。发酵代谢的活性和产物均下降。全面的，