Ultrasound Priming Enhances Seed Vigor and Multiple Stresses Tolerance in Aged Maize Seeds
AbstractSeed aging leads to reduced germination rates and vigor, particularly under stress conditions. We subjected aged maize seeds to 40 seconds of ultrasonic treatment, which enhanced their vigor and tolerance to combined stress. The ultrasonic treatment increased more cracks and holes in the seed coat, thereby promoting water absorption. Concurrently, it improved the germination and root growth of aged seeds under combined stress, with enhancements observed in endogenous hormone levels, antioxidant enzyme activity, osmotic regulators, and hydrolase content. Under combined stress, ultrasound activated transcriptional and metabolic reprogramming in aged seeds, not only triggering more pathways associated with growth and defense but also activating the MAPK signaling pathway. Through structural, physiological and molecular reprogramming, ultrasound treatment enhanced the vigor and stress tolerance of aged seeds, providing an effective strategy for revitalizing stored seeds and coping with multiple stresses under adverse conditions.