Structural and physiological adaptations of oat (Avena sativa L.) adaptation to low temperature and waterlogging stress under climate change

Oat ( Avena sativa L.), a significant cereal crop, is increasingly challenged by climate change induced abiotic stresses particularly low temperature and waterlogging. These stresses frequently occur sequentially or concurrently in temperate production regions as oat cultivation expands toward higher latitudes. Although these stresses differ in their primary causes, they share common physiological consequences, including disrupted cellular homeostasis, oxidative stress, and extensive structural remodeling, highlighting the need for an integrated understanding of oat adaptation. Under low-temperature stress, oats exhibit relatively poor freezing tolerance owing to limited structural flexibility and less efficient activation of calcium-dependent and CBF/DREB1-mediated signaling pathways, resulting in greater susceptibility to freezing injury. In contrast, oats perform well under waterlogged conditions. In contrast, oats display relatively high tolerance to waterlogging through anatomical plasticity, including aerenchyma formation and adventitious root development, which maintain oxygen diffusion and root function under hypoxia via coordinated regulation by ethylene, ROS, and hormonal signaling. Emerging evidence further suggests potential cross-talk between low-temperature and waterlogging responses through overlapping regulatory networks involving ROS, hormonal signaling, calcium-dependent signaling, and cell wall remodeling. This review synthesizes current knowledge of oat adaptation to low-temperature and waterlogging stress from integrated anatomical and physiological perspectives, incorporating recent advances in microscopy-based studies. By linking tissue architecture with physiological regulation, it provides a comprehensive framework for understanding stress adaptation and identifying future strategies for improving climate resilience in oat.