博士 / 國立中興大學 / 生命科學系所 / 99 / The micropropagation and in vitro flowering of Begonia parvula H. Lév. & Vaniot, a highly ornamental wild species from China, were investigated. The in vitro conservation studies included reproductive biology, induced vegetative and floral organ regenerations, as well as in vitro flowering and biomass allocation under treatments of different concentrations of inorganic nitrogen. Results of this study were summarized below:
Chapter 1--Introduction: Begonia is a genus exceeding 1,600 species throughout the tropical and subtropical regions of world, with a long and distinguished history in cultivation. Many field surveys on begonias have been carried out throughout the world. Habitat destruction is known to be the biggest threat to the survival of Begonias. Begonia parvula was chosen as the subject material for the application of in vitro conservation technologies.
Chapter 2: In vitro flowering of B. parvula was investigated. Seeds were sown in a hormone-free defined medium (1/4 MS). Eight weeks after culture, seedlings were transferred to 1/2 MS medium. A period of 5.5 months elapsed from the seed state to the stage when male and female flowers were fully open. A comparison was made between the in vivo and in vitro male and female flowers. A number of the flowers’ reproductive organs in vitro were smaller than in vivo. Flowers of both in vivo and in vitro plants had identical reproductive organs. In vitro fruit ripening was observed and viable seeds were obtained 6 to 7 weeks after manual pollination. This study showed that the life cycle of B. parvula can be completely controlled in vitro.
Chapter 3: Adventitious bud regeneration on laminae of B. parvula was investigated in vitro. Adventitious bud regeneration was induced from material germinated from axenical seeds. 5×7 mm2 lamina explants were cultured on 1/2 MS containing BA, kinetin, zeatin, and NAA in varied concentrations and combinations. The optimal medium for adventitious bud regeneration and lowest occurrence of necrosis in explants was 1/2 MS supplements with 2.0 mg-1 zeatin and 0.5 mg-1 NAA. In 4.5-5 months, in vitro flowering developed from adventitious shoot explants after twice subculture on 1/2 MS hormone free basal medium.
Chapter 4: In vitro regeneration of the perianth organ of B. parvula was investigated. Heretofore, regeneration from tepal were unknown in explants of Begonia. The aseptic tepals from the in vitro flowering study were cultured on 1/2 MS medium supplemented with TDZ, BA, NAA in different concentrations and combinations, incubated in dark and regeneration observed after 4 weeks. The optimal level of plant growth regulator for shoot regeneration was 1.0 mg-1 TDZ with 0.05 mg-1 NAA. Histological examination revealed that morphogenesis took place as indirect organogenesis and somatic embryogenesis. In vitro flowering resulted from organogenesis occurs in in vitro tepal explants 5-5.5 months after incubation. Phenotypically normal potted plants were derived from tepal explants growing in the greenhouse after being transferred to soil for 4 weeks.
Chapter 5: Evaluation of the in vitro flowering and biomass allocation of B. parvula under six different levels, viz. 0, 9.41, 19.71, 30.03, 50.65, 91.89 mM, of inorganic nitrogen was conducted in defined 1/2 MS medium. The results indicated that the average scape number and scape length of in vitro flowering explants were highest after 19.71 mM nitrogen was applied for 16 weeks.. Eliminating inorganic nitrogen in the culture medium inhibited flower induction. However, high level of nitrogen (91.89 mM) appeared to have a negative effect on the growth and morphogenesis of the explants, with a significant lowering of biomass accumulation. The total dry weight of explants was also the highest in the treatment with 19.71 mM nitrogen. A positive linear relationship existed between SPAD-chlorophyll meter estimated values, scape number, scape length and total dry weight. It was concluded that a lowered concentration of nitrogen stimulated flower formation.
To sum up, the present work represents the first report of in vitro flower and fruit development from seeds of B. parvula. The in vitro flowers assumed normal morphology and the reproductive organs were fully functional.
| Identifer | oai:union.ndltd.org:TW/099NCHU5105024 |
| Date | January 2011 |
| Creators | Wei-Hsin Hu, 胡維新 |
| Contributors | , 彭鏡毅, 廖松淵 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 107 |
Page generated in 0.0017 seconds