The effect of post-harvest foliar spraying with gibberellic acid and calcium chloride on flower opening and its life

This experiment was conducted in the postharvest physiology laboratory of the Horticultural Sciences Department of Tabriz University, as a factorial experiment in a completely randomized design with three replications, in order to evaluate the effect of foliar spray treatments of gibberellic acid (0.5, 1, and 1.5 mM) and calcium chloride (5, 10, and 15 mM) alone and in combination with sucrose (0 and 2%) and 8-hydroxyquinoline sulfate at a concentration of 250 mg/L on the vase life of cut flowers of Black Magic. Cut flowers were kept at a temperature of 2±23°C, a relative humidity of 10±60%, and a light intensity of 12 μmol/m2/s (cool white fluorescent lamps) with 12 hours of lighting until the end of the vase life. The results showed that the highest amount of solution absorption was observed in the 1.5 mM gibberellic acid × 15 mM calcium chloride treatment, and the lowest amount of fungal contamination was observed in the 1 mM gibberellic acid × 15 mM calcium chloride treatment. The combined treatment of 1.5 mM gibberellic acid with 5 mM calcium chloride had the greatest effect on increasing the relative fresh weight of the branch. Also, the highest rate of flower blooming was observed in the combined treatment of 1.5 mM gibberellic acid with 10 mM calcium chloride. The highest chlorophyll fluorescence index was in the interaction of 0.5 mM gibberellic acid with 15 mM calcium chloride with an average of 80%. However, the treatments used had no effect on leaf chlorophyll index, ion leakage, stomatal conductance, and relative petal water content. Considering the positive effects of gibberellic acid and calcium chloride on flowerpot life, foliar spraying of these treatments with a concentration of 1.5 mM gibberellic acid and 10 mM calcium chloride on the flower life of the Black Magic rose cultivar is recommended.