| Summary: | 碩士 === 國立臺灣大學 === 園藝學研究所 === 87 === The ornamental Bromeliads(Bromeliaceae ) included Guzmania cv. Cheery、cv. Carine and Vriesea cv.Margo were collected for study of micropropagation via caulogenesis.
1. Shoot tip culture : The young suckers(3 ~ 8 cm) required intensive pre-sterilization. The compressed shoot tip(0.5 - 0.8 cm) splitted into 4-6 sections as explant benefit for apical dominance breaking and increase the number of adventitious buds. Numerously adventitious bud appeared in the leaf axil and gradually turn to green two months after culture. Two more months later, the bud become slightly longer and continuous to proliferate new bud .The regeneration medium used 1/2 MS supplemented with NAA 1.0 mg/L + TDZ 0.5 mg/L, showed high efficiency in stimulation of caulogenesis. In Guzmania cv.Cheery, achieved 39.2 buds per explant, the largest bud size was 0.73 cm. In Vriesea cv.Margo, formed 31.3 buds, with the largest budding size on average being 0.55 cm. The combination of NAA 1.0 mg/L and BA 1.0 mg/L induced 19.3 and 28.2 buds In"Cheery"and "Margo"respectively. The cytokinins contributed to massive bud formation or proliferation, but the clustered bud sprouting was restricted. The extended growth and rooting could be approached by transferring into 1/2 MS medium added GA 0.5~1.0 mg/L and NAA 0.5 mg/L. The anatomical study exhibited that the adventitious buds were directly initiated from the epidermal and subepidermal tissue of the elongating axil , and capable to proliferate from the meristematic surface tissue.
2. Leaf culture : The young leaves 1.5 - 3.0 cm in length of suckers were excised as explant. Which were inoculated on MS medium contained 2,4-D 1.0 mg/L,for de-differentiation of pale-yellow callus from leaf bases. The frequency of callogenesis was about 5-10%. The condition of 1/2MS medium with NAA 1.0 mg/L efficiently showed to friable callus, and to re-differentiate adventitious buds.
3. Floral tissue culture : The florets 2.5 - 3.0 cm in length of Guzmania cv.Cheery and Vriesea cv.Margo were excised as explant and inoculated on dedifferentiation medium. It was demonstrated that the callogenic capability was variable among different floret parts. More than 50% callus were achieved in petal and ovary explants of Guzmania cv.Cheery.
The floral tissues in petals and anther of the Vriesea cv.Margo, showed more easily to induce callogenesis. The desirable floral parts inoculated on MS medium supplemented with 2,4-D 0.5 mg/L formed pale-yellow callus. Take these callus into 1/2 MS medium added with NAA 1.0 mg/L, oncomitantly stimulated friable callus proliferation and numerously adventitious buds regeneration. Subsequently, the advance growth and multiplication of the petal callus-derived buds could be improved under 1/2 MS liquid medium supplemented with BA 1.0 mg/L condition for 20 days. The rooting could be approached by transferring into 1/2 MS medium contained NAA 0.1mg/L after solid culture.
4. Secondary explant culture : (1) Leaf-bud liquid culture: The outer leaf-buds were excised from microshoot, and transferring into 1/2 MS liquid medium supplemented with NAA 0.1 mg/L + BA 0.1 mg/L, on shaker 110 rpm. The axillary bud was sprouting from leaf basal by 3 weeks after culture. The average 4.3 neomicroshoots achieved from each microshoot. (2)Microshoot liquid culture: The petal-derived adventitious buds were excised and inoculated 1/2 MS liquid medium contained BA 1.0 mg/L which proliferated 3-4 shoots from each microshoot by 4 weeks after culture.(3) Microshoot solid-medium culture: The petal-derived adventitious buds were transferring into 1/2 MS solid medium supplemented with NAA( 0.1-1.0 mg/L) and cytokinin( 0.1-0.5 mg/L). It was demonstrated that the combination of NAA 0.1 mg/L and BA 0.1 mg/L induced 3-5 lateral buds sprouting and appeared normal growth.
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