Eco-friendly extension of postharvest longevity in Alstroemeria cut flowers using melatonin and putrescine treatments

Postharvest longevity is the most important factor concerning the commercial value of cut flowers. Alstroemeria 'Amatista' is one of the most valued species for its ornamental appeal and it has been often reported to suffer from premature senescence. The present study was undertaken to establish the efficacy of melatonin (100 and 200 μM) and putrescine (1.5 and 3 mM) as enviro-friendly compounds applied into the vase solution in extending the vase life of cut flowers of Alstroemeria by assessing different physiological parameters. Results showed that melatonin at 100 and 200 μM and putrescine at 1.5 mM significantly extended the flower vase life from 12 to 13 days (control) to 20-21 days. More precisely, both melatonin and putrescine lowered electrolyte leakage (EL) and increased relative water content (RWC), relative fresh weight (RFW), and relative solution uptake (RSU) of flowers. In addition, both compounds enhanced the total anthocyanin content, phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) activities, and reduced malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) content, which implies the decline in oxidative stress. These results confirm that both melatonin and putrescine act as effective and environmental-friendly exogenous applications to improve postharvest quality and extend the vase life of Alstroemeria cut flowers. The study provides important information for possible applications in the floriculture industry.