| Summary: | 碩士 === 國立中興大學 === 園藝學系 === 90 === Summary
Two cultivars of Gerbera jamesonii Bolus ’Furore’ and ‘Ornella ’ were tested in this study to investigate the physiological change, floret development and vase life of gerbera cut flowers at different maturity stages, time of dehydration, the chemical treatment and the treatment of exogenous ethylene.
The respiration rate, ethylene production, fresh weight change, water uptake, vase life, and flower quality of ‘Furore’ and ‘Ornella’ cut gerbera flower at different maturity stages were investigated. The highest respiration rate was found on non-anthesis monoclinous dicyclid florets after flowers harvested. The highest ethylene production was found on receptacle when flowers were cut and upper part stem in 6 days vase life. Cut flowers harvested at maturity with third circle stamens of monoclinous dicyclic florets presented the highest respiration rate, the highest ethylene production, and increased the earliest ethylene production. Highly maturity cut flowers contained higher starch content on the petal, gained more flower fresh weight, and larger flower diameter and water uptake than those of less mature cut flowers after flowers harvested. In stem tissues, cortex cells were round and complete. The number and size of vessels showed bigger diameter than that of younger tissues. However, over maturity cut flowers were easily bend on ‘Ornella’ gerbera and showed easily bluish and decreased vase life on ‘Furore’ gerbera flowers. Gerbera cut flowers harvested on bud stage had the advantage of the low respiration rate, low ethylene production, and slower ethylene increased trend, however, flower diameter presented smaller when flower bloomed, florets was fade caused poor flower quality. The good gerbera flower performance showed the requirement with ray florets fully open, disk florets were not open yet, and considered the maturity of one or two of the stamens of monoclinous dicyclic florets could result flower diameter, vase life, and flower color performed well.
There were more ethylene rate, water loss rate and osmotic potential, immediately after harvest and transient water stress. The water loss rate of ‘Furore’ gerbera cut flowers was 0.97% after one hour of water stress, but it increased to 15.4% after 24 hours of water stress. The water potential was -0.5 MPa after one hour of water stress but it increased to -0.8 MPa after 12 hours of water stress. The water loss rate of ‘Ornella ’ was 3.51% after one hour of water stress, but it increased to 18.3% after 24 hours of water stress. The water potential was -0.8 MPa after one hour of water stress but it increased to -1.2 MPa after 12 hours of water stress. Besides, water stress also caused the decrease of respiration rate and the water uptake in the early rehydration of gerbera, but it had no significant effect on the electrolyte leakage rate and fresh weight of the floret base. The vase life and scape bending were also influenced by cultivars. The exposure to water stress resulted in shorter vase life and more scape bending of ’Furore’. However, there were no significant effects on the vase life and scape bending of ’Ornella’.
There were no significant effects on the vase life and flowering performance after the treatment with exogenous 0~10 ppm ethylene and 24hr wet transportation. The respiration rate and ethylene rate increased with exogenous ethylene concentration. However, there were no significant effects on the vase life afterward. There were no significant effects on vase life after the treatment with ATA, 1-MCP, Retain and STS. However, the vase life prolonged after pulse treatment with DDMH, NiCl2 and sucrose for 2hr, and the scape bending of the ‘Ornella ’ cut flowers would be improved.
Therefore, the results showed that it was better to harvest the gerbera flowers at the stamens of monoclinous dicyclic florets were at one or two of the stamens of monoclinous dicyclic florets mature stages. The vase life prolonged and the scape bending would be improved after pulse treatment with DDMH, NiCl2 and sucrose for 2 hours.
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