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).
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