The objectives of this study were to develop an in vitro direct adventitious bud induction and an organogenic callus induction and shoot regeneration system via floral organ segments culture for bromeliads, moreover, explore the effect of auxin on plantlet elongation of Guzmania. And further, apply the above micropropagation system to physical and chemical methods to induce somaclonal variances of bromeliad plantlets in vitro for mutation breeding.
The explant sources of bromeliads and the components of culture medium were studied to develop a micropropagation system for bromeliads. The results indicated that the 1/3MS basal medium supplemented with a combination of 1.0 mg l-1 BA + 0.5-1.0 mg l-1 NAA, or a combination of 3.0 mg l-1 BA + 0.5 mg l-1 NAA, showed the highest frequency of direct initiation of adventitious buds derived from shoot apex and lateral bud explants of Aechmea fulgens var. fulgens and Guzmania 'Focus'. The best results of adventitious buds induction of the both species were found in the lower lateral bud explants, at 47.5% and 35%, respectively. In addition, the adventitious buds began to form on day 16 after the G. 'Focus' decapitated plantlets had been cultured in medium supplemented with 3.0 mg l-1 BA + 0.5 mg l-1 NAA. However, this phenomenon did not occur in case of undecapitated explants, where only protruding nodules appeared.
Petal- and ovary-derived calli of A. fasciata and G. 'Hilda' were induced on 1/2MS basal medium supplemented with 1.0-1.5 mg l-1 2,4-D in combination with 1.0 or 0.5 mg l-1 NAA. Organogenic calli were cultured on medium with 1.0 mg l-1 NAA and 0.5 mg l-1 TDZ could be induced to differentiate and regenerate the adventitious buds. Furthermore, the number of adventitious buds proliferating at the base of the plantlets derived from G. 'Hilda' floral organs, cultured in media with different concentrations of IAA, IBA, NAA, and 8-azaadenine, was only 1-2 adventitious buds individually. This result shows that auxin can indeed suppress cytokinin-effects. The influence on plantlet elongation was greatest in the treatments using 0.5 mg l-1 NAA and 1.0 mg l-1 NAA. After 4 months culture, plantlets grew to 5.73 and 5.62 cm in height, that was 2.22 and 1.95 cm higher than the control, respectively.
Plantlets of A. fasciata hardened under the middle (50 £gmol m-2s-1) light intensity condition had a higher survival rate, 95%, than that hardened at a low light intensity (1 £gmol m-2s-1; 17.5%). The maximum number of newly developing roots, up to 4.15 per shoot, was also observed at the same light intensity treatment. During transplantation, plantlets growing in coir fiber showed the best results in terms of plant growth within 6 months ex vitro culture. The average length of the plantlets was 22.0 cm, and an average of 19.3 leaves per plantlet was achieved.
When calli of G. 'Hilda' treated by sodium azide, the survival rate was 0%. The survival rate of decapitated plantlet explants treated with 0.5 mM sodium azide for 60 minutes was 51.3%, about half-lethal dose. In addition to the survival rates of decapitated plantlet explants of A. fasciata, G. 'Hilda', G. 'Cherry', G. 'Luna' and G. 'Focus' irradiated by £^-ray showed 74.2-100% with the exception of the G. 'Focus' irradiated by 15 Gy, which dropped to 45.0%. At present, mutant plantlets showed a great deal of chimeras in leaf and were transplanted to potting media.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-1212111-134921 |
| Date | 12 December 2011 |
| Creators | Huang, Ping-Lung |
| Contributors | Hsien-Jung Chen, Zin-Huang Liu, Li-Jen Liao, Wen-Huei Chen, Yao-Huang Chen |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1212111-134921 |
| Rights | user_define, Copyright information available at source archive |
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