Post-Anoxia in Plants: Reasons, Consequences, and Possible Mechanisms

One of the adverse factors affecting plants is oxygen deficiency, which develops as a result of excessive waterlogging and flooding. In a natural habitat, following a period of oxygen deficiency, aerobic conditions are usually restored, resulting in exposure of plants to post-anoxic oxidation conditions. The endogenous reduced metabolites and soil toxins accumulated during oxygen deficiency begin to be oxidized by atmospheric oxygen, which leads to the generation of reactive oxygen species (ROS) and the development of damage that can cause the death of a plant even if it has survived anoxic conditions. Recent studies discussed in the review indicate that the main mechanisms of adaptation to the post-anoxic period are mainly the biosynthesis of antioxidants and the effective operation of antioxidant system, the activation of alternative oxidase and detoxification of anaerobic metabolites. Ethylene-dependent transcription factors ERF-VII, which are also involved in the regulation of adaptation directly to oxygen deficiency, as well as phytohormones, such as jasmonic and abscisic acids, play an important role in ensuring the regulation of adaptation to post-anoxic conditions. Post-anoxia should not be considered as an independent stressor, since it represents a complex effect (the effects of anoxia, oxidative stress, and desiccation together contribute to the development of damage), and adaptation mechanisms and their regulation have many common elements with adaptation to oxygen deficiency.