Melatonin Preserves the Postharvest Quality of Cut Roses through Enhancing the Antioxidant System

The vase life of cut rose is relatively short, therefore; preserving its postharvest quality via eco-friendly approaches is of particular economic importance. From the previous literature, despite melatonin (MT) plays diverse important roles in the postharvest quality maintenance, its impact on preserving the postharvest quality of cut flowers is really scarce. This research therefore was undertaken to find out the possibility of exogenous MT as an eco-friendly preservative to extend the vase life of cut roses. The flowering stems of Rosa hybrida cv. 'First Red' were pulsed in MT solutions at 0, 0.1, 0.2 and 0.3 mM for 30 min and then transferred to distilled water for evaluation. The vase life was significantly prolonged and relative water content was considerably maintained due to MT application compared to the control, more so with 0.2 mM concentration which nearly doubled the vase life (1.9-fold) higher than the control. SEM investigation showed that MT treatment reduced the stomatal aperture in lower epidermis which was widely opened in control flowers. MT treatment significantly increased the phenol content, glutathione (GSH) content and CAT, APX and GR enzyme activities compared to untreated flowers. Additionally, the radical scavenging capacity in MT-treated flowers was considerably higher than that of control and therefore MT treatment reduced H₂O₂ production and lipid peroxidation, which altogether reflected in membrane stability maintenance.