Investigations into the cause and prevention of corolla abscission of Streptocarpus xhybridus Voss. during shipping (postharvest).
Agnew, Nancy Howard.
Thesis of Ph.D., Kansas State University, 1984, 73 pages
1984
บทคัดย่อ
Research was conducted to determine the cause(s) and prevention of corolla abscission during postharvest shipment of Streptocarpus Xhybridus Voss. Pollination was determined not to be a factor in corolla abscission. Pollination studies and the observation of pollen tube growth via fluorescence microscopy proved that natural pollination is infrequent in the cultivars Marna and Velma. Only 0.8% of the flowers examined had pollen tubes penetrating the style. A notable result of this work is the effect of pollination on ethylene evolution by the flowers. Pollination resulted in a 58% rise in ethylene evolution, a response not previously reported for this species.
Exposure of excised flowers and intact plants to various concentrations of 1-aminocyclopropane-1-carboxylic acid and a simulated shipping environment showed that ethylene was determined to be the agent of corolla abscission in Streptocarpus. Further work with cycloheximide showed that protein synthesis is a prerequisite for ethylene-induced corolla abscission. Studies involving the use of ethylene inhibitors and altered shipping temperatures showed that 0.5 mM silver thiosulfate sprays at 25(DEGREES)C reduced corolla abscission 88% over the control treatment and that the reduction of shipping temperature from 25 to 5(DEGREES)C lowered corolla abscission 90% for 'Marna'. Spray treatments of 0.1 mM benzylaminopurine, 0.5 mM sodium benzoate and 0.1 mM aminoethoxyvinylglycine were ineffective in reducing corolla abscission significantly. It should be noted, however, that aminoethoxyvinylglycine showed promise in reducing corolla abscission and should be subjected to further testing.
Studies with an unnamed blue seed variety of Streptocarpus centered on finding appropriate rate and timing of silver thiosulfate spray. Sprays applied 24 hours prior to shipping resulted in necrotic lesions on flowers and foliage and an increase in corolla abscission, whereas sprays applied 1 or 4 weeks prior to shipping effectively reduced corolla abscission. Spray concentrations of 0.5, 1.0, and 2.0 mM were all effective in reducing corolla abscission when timed appropriately.