Melatonin improves the postharvest life of cut ruscus foliage after a long storage condition

This study aimed to investigate the effects of various pulse treatments on the postharvest longevity and physiological quality of cut Danae racemosa branches. The cut foliage was treated with deionised water (CTRL), 10 μM thidiazuron (TDZ), 100 μM melatonin (MEL), 300 μM 5-aminolevulinic acid (AA), 300 μM ascorbic acid (VIT C), and 300 μM tocopherol (VIT E) for 24 h. The foliage was then subjected to simulated refrigerated transport (four weeks, at 6–8 °C in the dark) and retail conditions for up to 30 d (photoperiod: 12 h light/dark, light intensity: 50 μmol m⁻² s⁻¹, temperature: 20–24 °C). Measurements included the water uptake rate, weight change, vase life, chlorophyll a fluorescence, colour index, chlorophyll content, ethylene production, and hormone balance. The results showed that TDZ or MEL treatments improved the water balance, delayed senescence, and enhanced photosynthetic efficiency, with higher chlorophyll concentration (1.3–1.6 g kg−1 FW) and avoided ethylene increase (0.2–0.3 pL kg−1 h−1). Hormonal analysis revealed a decrease in ABA and an increase in cytokinin content in MEL-treated branches, indicating the role of MEL in modulating hormonal balance to extend vase life. These findings indicate that MEL is an effective postharvest treatment for preserving the visual and physiological quality of cut foliage, comparable to the well-established benefits of the TDZ.