Spraying Arginine at 5 Days before Harvest Delays Postharvest Broccoli Senescence via Nutrient Accumulation

To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli, arginine spraying (5 mmol/L) was conducted at 0, 1, 3, and 5 days before harvest. The appearance, respiration rate, mass-loss rate, electrolyte leakage, glucosinolate, ascorbic acid, total phenol, total flavonoid, total sugar and sucrose contents, and sucrose phosphate synthase (SPS), invertase (INV), sucrose synthase synthesis (SSS) and cleavage (SSC) activities of broccoli samples were observed after 0, 2, 4, 6, 8, and 10 days of storage. The results showed that spraying arginine at 5 days preharvest (5-ARG) helped to inhibit broccoli respiration during storage, delay electrolyte leakage, and maintain broccoli color. Furthermore, during the growth stage, total sugar accumulation was higher in the 5-ARG group. In addition, during the storage period, sucrose synthesis was accelerated, while sucrose cleavage was inhibited, resulting in more sucrose retention in postharvest broccoli. In conclusion, 5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage, thereby prolonging the shelf life of broccoli. Therefore, this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.