Cut flowers of spray chrysanthemum (Dendranthema grandiflorum (Ramat.) S. Kitamura) cv. White Polaris were harvested and treated in pulsing solutions. The flowers were harvested in commercial greenhouses and transported to the laboratory where the whole stem and inflorescence were immersed in tap water at darkness, during 3 hours. The flowers were selected for uniformity in terms of development; the stems were trimmed to equal length (50 to 60 cm) and tagged to allow recording morphological changes associated with individual flowers. The flowers were held during 24 hours (pulsing treatment period) at 25 ± 2°C and 60 to 90% of air relative humidity under continuous cool white fluorescent light at 1.5 KLx. At the end of the treatment, the flowers were transferred to distilled water, under daily 10 hours of continuous fluorescent light and at the same laboratory conditions already described. At the first experiment, it was tested the efficiency of 8-hydroxyquinoline (8-HQ) and thiabendazole (TBZ), as germicides, in three concentrations each one. Furthermore, two growth regulators were applied in order to keep the green color and the turgidity of leaves: gibberellic acid (GA3), 6-benzylaminopurine (6-BA) and a mix of them. At the second experiment, in order to extend the vase-life by inhibition of ethylene production, it was tested the effect of silver nitrate (AgNO3), anionic silver thiosulphate complex (STS) and cobalt chloride (CoCl2) into pulsing solutions in three concentrations each one. The results of experiments showed that pulsing treatment with distilled water + 0.52 mol/m³ citric acid + 58.43 mol/m³ sucrose + 0.69 mol/m³ 8-HQ + 2.9 or 4.4 mol/m³ AgNO3, combined with foliar treatment of 0.058 mol/m³ GA3, improved the foliar quality and extended the flower vase life.
chrysanthemum; postharvest; germicides; ethylene inhibition