The Critical Journey from Seed to Seedling: Surviving Abiotic Stress During Plant Establishment

Plant establishment, encompassing seed germination and early seedling development, represents one of the most critical and vulnerable phases in the plant life cycle. During these transitions, plants encounter a wide range of abiotic stresses, which impair survival and establishment, ultimately affecting crop productivity. This review synthesizes current knowledge on the physiological, biochemical, and molecular mechanisms during the seed-to-seedling transition and responses to major abiotic stresses, such as drought, salinity, extreme temperatures, waterlogging, nutrient imbalances, and variable light. During germination, drought and salinity disrupt water uptake and imbibition kinetics and trigger hormonal signaling, osmotic adjustment, and antioxidant defense responses. Extreme temperatures further alter metabolic activation, enzyme stability, and membrane integrity, thereby affecting germination success. In contrast, waterlogging induces hypoxic conditions, which impair aerobic respiration and trigger adaptive responses such as anaerobic metabolism, fermentation, and aerenchyma formation. In parallel, the transition from skotomorphogenesis to photomorphogenesis requires precise coordination of phytochrome- and cryptochrome-mediated signaling networks, ensuring successful seedling emergence under variable light environments. Nutrient stress, including both deficiency and toxicity, affects reserve mobilization, root system architecture, and early seedling vigor. Emerging strategies, including seed priming, biopriming, nanotechnology-based interventions, and molecular breeding, are also discussed as approaches to enhance stress resilience during establishment. A deeper understanding of stage-specific regulation and mechanisms during seed-to-seedling development can provide critical insight for developing climate-resilient crops that maintain robust establishment under increasingly variable environmental conditions.