• Korean Journal of Medicinal Crop Science
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• v.6 no.4
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• pp.294-298
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• 1998

The factors affecting direct somatic embryogenesis from different parts of explant in liquid culture of Scrophularia buergeriana were investigated. Direct somatic embryogenesis was dependent on the explant tissues and stem was the most efficient explant. Rapid shoot development occurred on stem after 3-week culture but roots were not developed yet. Plantlets were not formed through somatic embryogenesis after 3-week culture of petiole. Though direct somatic embryo was not observed from leaf segment culture for 3 weeks, normal plantlets were developed after 8-week culture. BA played the main role for somatic embryogenesis in liquid culture and adding of either IAA or NAA caused rather adverse effects. Culture of stem segments in MS liquid medium with BA at 0.5 mg/ l or 0.1 mg/ l was proved to be the most efficient method for producing plantlets through direct somatic embryos.

• Journal of Plant Biotechnology
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• v.50
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• pp.19-26
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• 2023

Korean ginseng (Panax ginseng Meyer) is an economically important plant because of it is rich in saponins. It is mainly cultivated in Asia, including Korea and China. Since ginseng requires a long breeding period due to juvenility, homozygote production techniques, such as anther culture, must be urgently established. In the present study, callus induction and embryogenesis through anther culture were observed in P. ginseng. Murashige and Skoog medium was used as the basal medium suitable for callus induction. When the medium was supplemented with 3% sucrose, the callus induction rate was high and the callus size was large. Cold pretreatment did not significantly affect callus induction and embryogenesis. Embryogenesis was the most efficient when the embryo-formation medium was supplemented with 1.0 or 3.0 mg/L 2,4-dichlorophenoxyacetic acid. Cultivar significantly affected anther culture efficiency. Specifically, 'Cheongseon' showed the highest embryo-formation efficiency, whereas no embryogenesis occurred in 'Sunun'. Ploidy assessment revealed the haploid status of the induced calli. Embryos derived from anther culture formed shoots upon transfer to germination medium, although no difference in ploidy was noted between the induced callus and control. Overall, the anther culture conditions established in the present study may contribute to the production of homozygous P. ginseng plants in the future.

• Animal cells and systems
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• v.1 no.2
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• pp.355-361
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• 1997

We have screened available chromosomal deficiencies on the X chromosome for genetic loci whose zygotic expression is required for body-wall muscle development during embryogenesis in Caenorhabditis elegans. Previously, it had been reported that no sign of muscle development was detected in nullo-X embryos arrested at an early stage of embryogenesis. Based on this observation, it has been suggested that genetic loci exist on the X chromosome whose zygotic expression is essential for body-wall muscle formation. In order to identify such myogenic loci, 9 chromosomal deficiencies covering approximately 45% of the X chromosome have been tested. Homozygous embryos from these deficiency strains were collected and terminal phenotypes of arrested embryos were observed by Nomarski microscopy. As a secondary assay, monoclonal antibodies against two myosin heavy chain (MHC) isoforms, the products of the myo-3 and unc-54 genes, were used to detect body-wall muscle differentiation. All the homozygous deficiency embryos were positively stained with both MHC antibodies and muscle twitching movement was observed in most cases. Combined with previously analyzed deficiencies, our deficiency screen has covered approximately 70% of the X chromosome. We conclude that the regions covered by the available deficiencies on the X chromosome do not include any myogenic locus required for body-wall muscle formation. Alternatively, the possibility that nullo-X embryo may not form body-wall muscle due to a general failure to differentiate during embryogenesis remains to be tested.

• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.1
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• pp.75-78
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• 2007

To define the molecular mechanism of initiation and termination of diapause during the embryogenesis of silkworm, Bombyx mori, mRNA transcripts from diapausing eggs and diapause activated eggs were compared with differential expression using cDNA array. Among those clones, mRNA transcript from hsp20.8A, which was expressed at a high level in diapausing eggs that had been incubated at $25^{\circ}C$ for 30 days after oviposition, whereas, in the eggs exposed to $15^{\circ}C$ for 30 days, $5^{\circ}C$ for 60 days, the expression of mRNA decreased. On the other hand, the expression of mRNA during embryogenesis observed abundantly at 4 to 6 days after heat-HCl treatment and later at 9 to 10 days after just before hatching. This result was suggested for us that hsp20.8A was expressed in response to embryogenesis as well as physical stress.

• Korean Journal of Plant Resources
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• v.8 no.2
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• pp.153-157
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• 1995

Embryogenic callus induces from shoot tip and leaf segment of Zanthoxylum piperitum for producing somatic embryogenesis and plant regeneration were cultured in vitro on Murashige and Tucker's(MT) medium treated with casein hydrolysate $NH_4NO_3$, $KNO_3$ and plant growth regulator. The most effective somatic embryogensis was observed in the medium added by two fold $NH_4NO_3$(3300mg/l)+2. 4-D 0.1mg/l and $KNO_3$(3800mg/l)+2.4-D 0.1mg/l. Also, MT medium supplemented with casein hydrolysate 700mg/l added by 2, 4-D 0.1mg/l were effective in obtainingn somatic embryos from embryogenic callus The effect ofm MT medium supplemented with casein hydrolysate without 2, 4-D was lower than that with (3300mg/l) 2, 4-D for the formation of somatic embryos.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.67-72
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• 2004

An efficient protocol has been developed for rapid mass propagation of sweetpotato from shoot-tips derived embryogenic callus. Optimal embryogenic callus was induced from shoot apical meristem explants on Murashige and Skoog (MS) medium supplemented with 1mg/L 2,4-D. The addition of casein hydrolysate in the media increased the embryogenesis efficiency of sweetpotato. Somatic embryos were easily induced from the embryogenic callus on MS basal medium containing 300-500mg/L casein hydrolysate without phytohormon. Treatment of casein hydrolysate (100∼300mg/L) with 1mg/L 2,4-D also improved the secondary embryonic efficiency from somatic embryos below 2mm in length. Plant regeneration was achieved via somatic embryogenesis and direct organogenesis. Regenerated planlets with well developed shoots and roots on MS basal medium were successfully transferred to soil.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.157-164
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• 1995

Intact mature zygotic embryos or their excised cotyledons of ginseng, were cultured on media containing various growth regulators such as auxin (2,4D, IAA) and cytokinin(BAP kinetin). In the culture of intact zygotic embryos, auxin inhibited germination but cytokinin did not Somatic embryogenesis occurred only from those of ungerminated embryos. In the culture of cotyledon segment, medium without growth regulators was the most appropriate to somatic embryogenesis. Somatic embryos were produced sporadically over the surfaces of zygotic embryos on medium containing auxin, while on medium without growth regulators, or media containing cytokinin, somatic embryos formed only on the proximal region of cotyledon. on medium containing 2,4-D, somatic embryos originated from multiple cells which comprised epidermal and subepidermal layers of cotyledon, which resulted in poly-somatic embryogenesis. When these somatic embryos were cultured on the same medium, the primary somatic embryos procured secondary embryos, which arose from epidermal or subepidermal single cells.

• Journal of Plant Biotechnology
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• v.33 no.4
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• pp.243-248
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• 2006

A optimal procedure for plant production via repetitive secondary somatic embryogenesis in Tilia amurensis is described. Somatic embryos were induced directly from the culture of zygotic embryos on medium with 1.0 mg/l 2,4.-D. Repetitive secondary somatic embryos formed on the surface of the cotyledons and hypocotyls except for the radicles when explants of somatic embryos were cultured on medium with 4.0 mg/l 2,4-D. The highest frequency of secondary embryo-genesis was obtained in the cotyledons (90%) and hypocotyls(83.33%) on MS medium with 1.0 mg/L 2,4-D. The average number of secondary embryos per explant was 25.74 in cotyledon and 24.92 in hypocotyl. When the cotyledon and hypocotyl segments from somatic embryos at different developmental stages were cultured on MS medium with 1.0 mg/L 2,4-D, the highest frequency of secondary embryogenesis was obtained from late cotyledonary secondary embryos. Somatic embryos were transferred to MS basal medium and then they germinated within 2 to 4 weeks of culture. Germinated somatic embryos grew normally into plantlets on WPM medium, producing new shoots. The converted plantlets were acclimatized on artificial soil mixture. These results indicate that the repetitive secondary somatic embryogenesis in T amurensis can offer the possibility to use in vitro culture system for the micropropagation.

• Plant Biotechnology Reports
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• v.3 no.4
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• pp.333-340
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• 2009

Developmental anomalies in the plumule meristem of peanut (Arachis hypogaea L.) somatic embryos resulted in poor shoot differentiation and reduced plant recovery. Existing meristems with caulogenic potential have never been tested for embryogenesis in peanut. The present experiment was designed to test the mature zygotic embryo axis derived plumule with three meristems for somatic embryogenesis. Embryogenic masses and embryos developed from the caulogenic meristems in the axils. Exposure of 2 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation temporarily which then regained the ability to form the shoot on withdrawal of 2,4-D. Exposure of 4 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation irreversibly. No shoot formation was noted from the tips in any of the cultures which were in secondary medium with $13.6{\mu}M$ 2,4-D. Development of somatic embryos directly from axillary meristems was confirmed histologically. Conversion frequency of these embryos was 11%. Thus, in this report, we describe a method to obtain somatic embryos from the determined organogenic buds of the axillary meristem, by culturing the nodal explant vertically on embryo induction medium. It also displays the possibility of obtaining both embryogenic and organogenic potential in two parts of the same explant simultaneously. The possibility of extending this approach for genetic transformation in in vivo system through direct DNA delivery or Agrobacterium injection in meristems can also be explored. Using Agrobacterium rhizogenes, we have demonstrated the possibility of gene transfer in the axillary meristems of seed-derived plumule explant.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2000.10a
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• pp.114-115
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• 2000

Aralia elata is found in mountain areas all over Korean peninsula. Aralia elata is the scientific name for Japanese angelica tree. The tree belongs to the family Araliaceae, commonly known as ginseng family. Bud sprouts from apical shoot tip of the plants are rich in flavor and thus mainly used for both folk medicine and vegetable. The stalks with apical buds are gathered in the early spring and planted in sandy soil or water in the greenhouse. The sprouting buds are then collected and sold as fresh vegetable. Although the plants have been used for food, they have been cultivated in a very small scale. In spring, local farmers just go around mountain areas to search the trees and gather the stalks as much as they get and sell them to the market. No conservation efforts have been made to stop the exploitation or to save the dwindling population. We tried to provide local farmers with the plants that may be used as an alternative to stalks from wild populations. This will bel! p conserve the wild populations. However, it is hard to propagate them either by conventional cuttings or by seed germination in a short period of time. Mass propagation using tissue culture systems have shown a great promise with several woody plants. Recently we developed a mass propagation technique via somatic embryogenesis system using mature and/or juvenile explants for Aralia elata. Several factors affecting somatic embryogenesis system including SE(somatic embryo) induction, embryogenic callus proliferation, SE germination, plant regeneration and transplanting to field frill be presented. And some problems arising for the somatic embryogenesis system will be also discussed.