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

Area of Science:

• Plant Science
• Horticulture
• Postharvest Biology

Background:

• Cut rose vase life is limited, necessitating effective postharvest preservation methods.
• Melatonin (MT) is known for various roles in plant quality maintenance, but its specific effects on cut flower longevity are under-researched.

Purpose of the Study:

• To investigate the potential of exogenous melatonin (MT) as an eco-friendly preservative for extending the vase life of cut roses.
• To evaluate the impact of different MT concentrations on the postharvest quality of cut roses.

Main Methods:

• Cut rose stems (Rosa hybrida cv. 'First Red') were treated with varying MT concentrations (0, 0.1, 0.2, 0.3 mM) via pulsing.
• Post-treatment, stems were placed in distilled water for vase life evaluation.
• Scanning Electron Microscopy (SEM) was used to examine stomatal aperture.
• Biochemical analyses included phenol content, glutathione (GSH) levels, and antioxidant enzyme activities (CAT, APX, GR).

Main Results:

• Melatonin application significantly prolonged vase life and maintained relative water content compared to the control.
• The optimal concentration of 0.2 mM MT nearly doubled the vase life (1.9-fold increase).
• MT treatment reduced stomatal aperture, increased phenol and GSH content, and enhanced CAT, APX, and GR enzyme activities.
• MT increased radical scavenging capacity, reduced hydrogen peroxide (H₂O₂) production and lipid peroxidation, ensuring membrane stability.

Conclusions:

• Exogenous melatonin effectively extends the vase life of cut roses.
• MT acts as an eco-friendly preservative by improving water status, reducing water loss, and enhancing antioxidant defense systems.
• The findings support the use of melatonin for maintaining postharvest quality and extending the ornamental value of cut roses.