Studies on Tissue Culture of Heliconia psittacorum cv. Rhizomatosa
| Autor: | Yih-Juh Shiau, 蕭翌柱 |
|---|---|
| Jazyk: | zh-TW |
| Rok vydání: | 1999 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 87 The genus Heliconia L. is represented by more than 200 species of tropical plants that constitute the family Heliconiaceae. The heliconia inflorescence is a colorful, multi-bracted structure which may be upright or pendent. Heliconia psittacorum L.f. and some of its hybrids (e.g., ‘Golden Torch’) are particularly promising because of their attractive flowers, long straight clean peduncles, prolific year round flower production, and show considerable potential as commercial cut flower. The main objectives of the present investigation were- (1) to standardize a method of in vitro propagation of Heliconia psittacorum cv. Rhizomatosa by culturing terminal and axillary shoot tips of rhizomes; (2) to induce callus in leaf, ovary and shoot tip explants for its intended use in mutation breeding; (3) to identify and control bacterial contamination in explants cultured in vitro. The results are summarized as follows: 1. Six strains of bacteria were isolated and characterized from in vitro cultured explants of H. psittacorum cv. Rhizomatosa. All of them were Gram negative, and identified as Agrobacterium radiobacter, Pseudomonas diminuta, Pseudomonas putida, Serratia marcescens, Sphingomonas pancimobilis and Xanthomonas campestris. 2. Lower contamination rates were obtained in leaf and shoot tip explants when surface sterilized by a two-step method. In the first step, the explants were sterilized with 0.5％ sodium hypochlorite for 15 min outside the laminar flow. In the second step, before resterilization in the laminar flow, the midrib of the leaf explants and three leaves covering the shoot tip explants were removed and then sterilized with the same concentration of sodium hypochlorite used in the first step, for five minutes. The explants were washed 3-4 times with sterile distilled water after each sterilization step. 3. A lower rate of contamination was obtained in explants collected from donar plants grown in the medium without soil [HydropelletsR:tree bark (1:1 v/v) ] in the greenhouse. 4. Lower contamination rates were obtained in overy and shoot tip explants pretreated with liquid MS medium containing either 500 mg/l cefotaxime for 3 days or 100 mg/l streptomycin+50 mg/l gentamycin for 2 days. Pretreatment of explants with antibiotics did not inhibit either callus formation in leaf explants or growth of shoot tip explants. 5. Pre-treatment of explants (leaf, ovary, and shoot tip) with hot water (40.2-45.2℃) did not help in controlling contamination in in vitro cultures. 6. Addition of BenlateR, an antifungal agent, in the culture medium was not useful in controlling contamination in leaf and ovary explants. 7. WPM basal medium supplemented with 2 mg/l 2,4-D＋2 mg/l kinetin supported highest ﹪induction of callus in leaf and ovary explants compared to explants cultured on MS and B-5 medium. However, MS medium supplemented with 2 mg/l BA＋0.5 mg/l NAA supported growth of shoot tip explants. 8. Age of the explants (ovary and leaf) was found to be critical in callus formation. The ovary explants collected from 14-26 days old inflorescence produced maximum callus without necrosis or browning when cultured on WPM medium supplemented with 2 mg/l 2,4-D+2 mg/l kinetin. Higher ﹪induction of callus with low ﹪browning was observed in leaf explants taken after 4-8 days of emergence from the shoot tip. 9. Well developed plantlets of Heliconia psittacorum cv. Rhizomatosa were successfully obtained after 3 months of culture of shoot tip explants on MS medium supplemented with 4-8 mg/l BA 0.5 mg/l NAA. Addition of 0.01 mg/l TDZ in the medium was found to be benficial for rapid growth of plantlets from shoot tip explants. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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