Vascular occlusion caused by the growth of microbial agents is one of the major factors contributing to premature aging, neck bending, and decreased vase life of cut gerbera flowers. In this study, a factorial experiment was conducted based on a completely randomized design with 3 replications in the year 2022 at a temperature of 21±1°C. The first factor included concentrations of 0, 0.5%, 1%, 2%, and 3% of eucalyptus hydroalcoholic extract, and the second factor included three different time points for assessing various flower traits post-harvest (at harvest, 4 days, and 8 days). The results indicated that with an increase in the holding time of flowers post-harvest, the bacterial population in the vase solution and neck bending increased. However, treatments with eucalyptus extract effectively reduced the bacterial population in the vase solution, resulting in decreased neck bending and increased vase life of gerbera flowers, cultivar "Pink Elegance," compared to the control sample. Among these treatments, the 2% and 3% concentrations showed better results compared to other treatments without significant difference between them. Furthermore, the eucalyptus treatments reduced electrolyte leakage from petal cells and the content of hydrogen peroxide and proline in flowers, while maintaining the antioxidant capacity and catalase enzyme activity in the treated flowers compared to the control. Therefore, based on the present findings, the application of 2% eucalyptus extract is recommended as the superior treatment for post-harvest cut gerbera flowers.
