Perception, Physiological Mechanism and Biological Protection Strategies Against Frost Stress in Orchard Systems: A Review and Future Perspectives

Fruit crops in orchard systems are highly vulnerable to frost stress during preharvest growth, particularly at sensitive reproductive stages, resulting in substantial yield losses and reduced sustainability. Frost stress presents major challenges to agricultural productivity and causes substantial economic losses, further exacerbated by climate variability and inadequate orchard management. Frost injury is initiated by ice nucleation and cellular dehydration, followed by membrane destabilization, oxidative imbalance, and metabolic disruption, ultimately leading to reproductive damage, yield reduction, and quality deterioration. Although several traditional approaches, such as irrigation, heating, and air disturbance, are used to avoid frost injury, they have some limitations in efficiency. Consequently, biological strategies with mechanistic, low-cost and eco-friendly characteristics have gained considerable attention as promising alternatives. Mitigation strategies include the application of cellulose nanocrystals (CNC), phytohormones, biostimulants, coating technologies, and molecular approaches, which are critical for improving frost resilience during frost events. These approaches regulate ice nucleation, enhance stress signaling and antioxidant capacity, and help maintain yield stability. Nevertheless, a comprehensive review addressing recent progress in this field remains lacking. Overall, biological treatments present remarkable potential for frost mitigation, but their success depends on better understanding of how these processes work across scales and in the field. This review aims to provide a basis for developing more effective and integrated frost strategies.