Experiments were conducted to study the interaction of cultivar, flower stage, silver thiosulfate (STS), and BA on flower senescence and leaf abscission in greenhouse-grown potted miniature roses. Plants of Rosa L. `Meijikatar' (Orange Sunblaze) and `Meirutral' (Red Sunblaze) were sprayed with several concentrations of STS and BA in factorial combination. In winter, plants were sprayed with STS at 0 or 2 mm and BA at 0, 0.02,0.04,0.11,0.22, or 0.44 mm In spring, flowers at three stages of development were sprayed with STS at 0,2, or 3 mm, and BA at 0, 0.02, 0.04, 0.22, or 0.44 mm One day after treatment in both experiments, plants were placed in darkness at 16C for 4 days to simulate shipping, and then they were evaluated in a controlled environment at 21C. Poststorage floral longevity (PSFL) was longer for `Meirutral' than for `Meijikatar' plants, regardless of chemical treatment or flower stage. Flowers that were in the bud stage (stage 1) before simulated shipping lasted longer than flowers showing color (stages 2 and 3), regardless of cultivar or chemical treatment. Combinations of STS and BA did not increase PSFL compared to STS alone. Plants treated with 2 or 3 mm STS exhibited longer PSFL than nontreated plants; however, 2 and 3 mm were about equally effective. STS at 4 mm was phytotoxic in a preliminary experiment. Applying BA alone did not affect PSFL, but did improve postharvest flower opening on `Meijikatar' plants about the same as STS applied alone. The large flowering cultivars represented by `Meijikatar' and `Meirutral' appear to be nonresponsive to BA. A star-shaped malformation was induced on `Meijikatar' and `Meirutral' plants by simulated shipping and was not prevented by STS or BA. Chemical name used: N-(phenylmethyl) -1H-purin-6-amine (BA).
Lisa Chen Cushman, H. Brent Pemberton, and John W. Kelly
Lisa Chen Cushman, H. Brent Pemberton, J. Creighton Miller Jr., and John W. Kelly
Simulated shipping (storage) experiments were conducted to determine the effects of shipping temperature and duration on flower longevity and leaf abscission of pot rose Rosa L. `Meijikatar' (= Orange Sunblaze) and `Meirutral' (= Red Sunblaze). In addition, three flower stages (1 = tight bud, calyx not reflexing; 2 = showing color, calyx reflexing, no petals reflexed; 3 = full color, petals beginning to reflex, traditional bud stage) were selected immediately prior to storing plants at 4, 16, or 28 °C for 2, 4, or 6 days. The experiment was conducted during the summer and repeated during the winter. Evaluations were made in an interior environment at 21 °C for both experiments. `Meirutral' exhibited longer poststorage longevity and less leaf abscission than `Meijikatar' in both experiments. Flowers of both cultivars advanced by about one stage during storage at temperatures greater than 4 °C in summer, but developed more slowly in winter. Results from both experiments showed that plants stored at 4 °C had the longest poststorage floral longevity, the best flower quality, and the least leaf abscission, regardless of cultivar, storage duration, or flower stage at the beginning of storage. For plants stored at 16 °C, floral longevity decreased and leaf abscission increased when the duration was longer than 4 days. At 28 °C, flower longevity decreased and leaf abscission increased, especially at durations longer than 2 days. In the winter experiment, there was no leaf abscission on plants placed in the dark at 21 °C and watered during storage treatments lasting up to 6 days. In the summer experiment, the younger the flower, the more it was negatively affected by high storage temperature. Overall, poststorage floral longevity was longer in the summer than the winter experiment.