Pre and postharvest spraying of arginine enhanced the stress resistance and promoted wound healing in broccoli during storage

Broccoli rapidly yellows and dehydrates post-harvest, causing a short storage life. Although arginine post-harvest has been shown to enhance broccoli's storage quality and shelf life, it remains unclear whether pre-harvest treatment yields similar benefits. The results showed that pre-harvest spraying of 5 mM arginine reduces the respiration rate and delays electrolyte leakage during broccoli's storage period, minimizing weight loss and yellowing and chlorophyll degradation. It also inhibits the degradation of ascorbic acid (ASA) and promotes the synthesis of total phenols, thereby increasing the total antioxidant capacity. Further studies showed that preharvest arginine spraying enhanced the activity of arginine decarboxylase (ADC), ornithine decarboxylase (ODC), and nitric oxide synthase (NOS). This accelerated the nitric oxide (NO) and the polyamine (PA) accumulation. Additionally, arginine aids in reactive oxygen species (ROS) balance and wound healing. Notably, preharvest arginine spraying was found to inhibit the hydrogen peroxide (H2O2) accumulation and enhance the activities of superoxide dismutase (SOD) and catalase (CAT), while also activating the phenylalanine ammonia lyase (PAL) and cinnamic acid 4-hydroxylase (C4H) activities. In conclusion, pre-harvest arginine spraying extends the broccoli's storage life and improves its storage quality by promoting endogenous arginine catabolism, ROS metabolism, and the wounds healing. Therefore, this study establishes a theoretical foundation for preharvest handling in post-harvest broccoli storage.