This study was carried out at the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, during the two successive seasons of 2004 and 2005 to investigate the effect of pre-storage pulsing treatments and storage periods on the physiological characteristics and chemical constituents of rose flowers (Rosa hybrida L. cv. First Red). The base of stem flowers were pulsed with (1) distilled water for 30 minutes (Control), (2) Florrisant 600 at a concentration of 10000 ppm for 4 hours, (3) Florrisant 600 solution at a concentration of 5000 ppm for 4 hours, (4) GA3 at a concentration of 20 ppm for 24 hours, (5) Kinetin at a concentration of 25 ppm + 8-hydroxyquinoline (8-HQ) at 150 ppm for 24 hours, (6) Sucrose at a concentration of 2% + AgNO3 at 1000 ppm for 30 minutes, or (7) AgNO3 at a concentration of 1000 ppm for 30 minutes. After that, the flowers were stored at a temperature of 2ºC and a relative humidity (RH) of 85-90%, in cold storage rooms for periods of 7, 14, 21 or 28 days.
Most of the pulsing solutions decreased the rate of fresh weight loss, respiration rate of flowers, but increased the total soluble sugars and total soluble phenols contents in petals and leaves, the anthocyanins and carotenoids contents in the petals, as well as the total chlorophylls and carotenoids contents in the leaves. Pulsing in a solution containing 25 ppm kinetin + 150 ppm 8-HQ for 24 hours gave the lowest rates of fresh weight loss and respiration, and the highest contents of total soluble sugars in the leaves, total soluble phenols in the petals and the leaves, anthocyanins and carotenoids in the petals.
The rate of fresh weight loss, and the contents of total soluble phenols in the petals and leaves were increased with increasing storage period. On the other hand, respiration rate, total soluble sugars in the petals and leaves, anthocyanins and carotenoids in the petals as well as total chlorophylls and carotenoids content in the leaves were decreased with increasing storage period.
A significant interaction was detected between the effects of pulsing solutions and storage periods on the rate of fresh weight loss, respiration rate, anthocyanins and carotenoids contents in the petals, as well as total chlorophylls and carotenoids contents in the leaves. Flowers pulsed with 25 ppm kinetin + 150 ppm 8-HQ for 24 hours and stored for 14 days gave an insignificantly different respiration rate compared to the lowest values, and gave total soluble sugars in the petals and leaves, total soluble phenols in the petals and leaves, anthocyanins and carotenoids in the petals insignificantly different than the highest values recorded for each characteristic. So, it can be recommended that Rosa hybrida cv. First Red could be stored for 14 days, at a temperature of 2ºC and a relative humidity of 85-90%, after pulsing in 25 ppm kinetin + 150 ppm 8-HQ for 24 hours, in order to maintain good physiological characteristics and chemical constituents of flowers.