Carbon Dot Nanozymes Rejuvenate Aged Seeds through ROS Homeostasis Regulation: A Three-Dimensional Coupled Seed Priming Strategy

Seed aging threatens global food security and crop genetic diversity. Carbon dots (CDs) have been extensively used to improve plant growth and stress resistance, but the rejuvenation effects and mechanisms of CDs priming in aged seeds remain unexplored. In this study, we synthesized citric acid-derived carbon dots (CA-CDs) with superoxide dismutase (SOD)-like activity to serve as a seed priming agent for rejuvenating naturally aged flowering Chinese cabbage seeds. Our study showed that CA-CDs priming regulated reactive oxygen species (ROS) homeostasis in aged flowering Chinese cabbage seeds by boosting their antioxidant defense system and directly scavenging ROS. This significantly enhanced seed germination, seedling establishment, seed reserve mobilization, and seed vigor in aged seeds, demonstrating remarkable rejuvenation effects. In particular, seed priming with 0.4 mg/mL CA-CDs exhibited the best rejuvenation effects. Moreover, our study innovatively developed a seed quality hallmark based on the SOD-like activity of CD SOD nanozyme and established a three-dimensional coupled seed priming strategy. We further validated their feasibility with metal-doped CDs and confirmed their cross-species applicability using accelerated aging seeds of Chinese cabbage, mustard, and tomato. This study provides theoretical insights and practical guidance for developing CDs priming agents and their rapid application in aged seed rejuvenation.