Our country has significant potential for the production and export of roses due to its favorable climate, abundant light, affordable labor, and strategic proximity to Middle Eastern and Russian markets. To ensure consumer satisfaction and market retention, exported flowers must meet acceptable quality standards. Since postharvest life is a crucial component of quality, extending it enhances the overall quality of the flowers and secures target markets. This study was designed in three parts to identify and investigate key factors influencing the vase life of cut roses. In the first part, eleven commercially popular rose varieties were eva‎luated based on their postharvest life, water absorption capacity, ethylene hormone production during aging, anatomical features, and membrane integrity throughout the postharvest period. Based on the findings, two varieties ‘Samurai’ and ‘Peach Avalanche’ were selected for further analysis, representing those with low and high postharvest longevity, respectively. The results indicated that varieties with longer postharvest life exhibited wider xylem vessels, thicker fiber walls, lower ethylene synthesis, reduced ion leakage, and decreased malondialdehyde levels. In the second experiment, gibberellic acid was tested at five concentrations (0, 50, 100, 200, and 400 mg/L) to determine the optimal level for improving postharvest life and related characteristics. The experiments, repeated twice for accuracy, revealed that a concentration of 100 mg/L yielded the best outcomes, including the highest water absorption, improved vascular traits, and increased lignin and calcium content—factors critical for stem strength, vascular integrity, and sustained water flow. This treatment also resulted in superior flower quality attributes, such as greater weight, larger bud size, and increased stem height. In the third experiment, the expression of genes involved in the lignin biosynthesis pathway was examined to confirm the effects of gibberellic acid. Paclobutrazol, a hormone synthesis inhibitor, was also tested, and the experiments were repeated twice. The results showed that gibberellic acid at 100 mg/L significantly enhanced postharvest life, water absorption, and anatomical characteristics supporting water flow, including vascular vessle diameter, fiber wall thickness, lignin content, photosynthetic pigments, petal soluble sugars, stem weight and height, and bud size, compared to the control. Conversely, paclobutrazol substantially reduced these traits, though its inhibitory effects were partially mitigated when combined with gibberellic acid. The increased expression of lignin biosynthesis genes (PAL, COMT, HCT, and PRPX) following gibberellic acid application confirmed its role in boosting lignin production, thereby enhancing the mechanical resistance of stems to collapse.

نعمت اله اعتمادي شلمزاري , مهديه غلامي

محمدحسين اهتمام , مجيد طالبي

سعيد ريزي , حميدرضا عشقي زاده , علي نيك بخت