Formation of Adaptive Defense to Low Temperatures in Arabidopsis thaliana

The effects of repeated cold stress on physiological, transcriptional, and metabolic processes was studied in Arabidopsis thaliana. An experiment included stages of initial chilling, acclimation, and repeated cold treatment. Repeated cold stress increased electrolyte leakage and decreased the chlorophyll a content, indicating a disruption of the membrane integrity and a restructuring of the photosynthetic apparatus. Expression analysis showed upregulation of the DREB1A, MYC2, COR15A, and COR15B genes, which are associated with the cold response and stress memory formation. Transcription of the flowering regulators FLC, HDA6, and HD2C was altered at the same time to balance adaptation and development. HPLC-MS revealed a significant accumulation of flavonoids, primarily kaempferol and quercetin derivatives, suggesting activation of antioxidant defenses. Taken together, the findings confirmed that repeated cold treatment activates a complex plant adaptation system based on the integration of physiological, transcriptional, and metabolic mechanisms. The formation of stress memory allows A. thaliana to maintain resistance and functional stability during repeated low-temperature exposures.