| Summary: | 碩士 === 國立中興大學 === 農藝學系 === 88 === In this study, the different parts of immature embryo derived from Arachis hypogaea(cv. TN11) where cultured on the MS basal medium supplemented with plant growth regulators such as NAA, 2,4-D, BA, and TDZ to find a efficent protocols for regeneration of plantlet via organogenesis or somatic embryogenesis.Results are summarized as follows:
1.The rates of shoot formation induced from epicotyl was highest than the other explants. The explants such as hypocotyl, whole cotyledon, half proximal cotyledon and half distal cotyledon have resulteed in low rates of shoot generation, but produced calli ranged from 64.14% to 77.13%.Of 6 different combined media containing 0.8 mg/l NAA and a wide range of BA (0.8~25.6 mg/l) used, the media with 0.8 mg/l NAA+ 3.2 mg/l BA and 0.8 mg/l NAA + 6.4 mg/l BA were more effective for induction of shoot.
2.The immature epicotyl and half proximal cotyledon have cultured on MS basal medium with different concentration of TDZ or BA. Except 4 mg/l BA induced 72.53% the explant produced shoot, the rates of shoot formation in media with other levels of BA were less than 50%. All media with BA only produced 2.3~2.94 shoots per explant. However, addition of TDZ was found to be better than BA in the rate and number of shoot formation. The optimal concentration of TDZ was at 4 mg/l ~ 8 mg/l. There are significant differences among genotypes for numbers of shoots generated per explant cultured on the MS basal Medium with 8 mg/l TDZ.
3.Observations for morphology of shoot induced with TDZ and BA indicated that BA induce normal shoot, but TDZ induce the small and thickened multiple shoot with primodia at the base of stem and axil.
4.The immature epicotyl and the half proximal cotyledon of TN11 were cultured on MS basal medium supplemented with 2,4-D at 0.5 ~ 16 mg/l. The results indicate that the induced efficience of somatic embryo from epicotyl was better than from the half proximal cotyledon.Of all media with 2,4-D used, 4mg/l 2,4-D had the highest rate at embryogenesis and produced a more number of normal somatic embryo. As 2,4-D level in induction medium increased to 8 mg/l or more, percent of embryogenesis decreased and was associated with browning of explants, and most of somatic embryo morphology was abnormal, and genotypic variation was found.
5.The treatment of 4 mg/l→2 mg/l 2,4-D have not increased the rates of second embryogenesis. Otherwise, somatic embryos which were induced from 2,4-D medium and then cultured on MS basal medium with TDZ could develop multiple shoots.
In order to induce shoot rooting, the shoots were cultured on the MS basal medium with different levels of NAA and IBA. The result showed the medium with 0.5 mg/l NAA had the best effect on the rooting rate of shoot in all inductation media. The medium supplemented with 50 mg/l ascorbic acid and 0.5 mg/l NAA could improve the growth and development of root system.
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