• Korean Journal of Plant Tissue Culture
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• v.21 no.1
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• pp.7-14
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• 1994

Immature zygotic embryos of five Korean soybean cultivars cultured on Murashige and Skoog's (MS) medium supplemented with various concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) produced somatic embryos without forming an intervening callus. The highest frequency (up to 90%) of somatic embryo formation was obtained when zygotic embryos were cultlued on medium containing 1 to 2 mga 2, 0-D in four cultivars. However the frequency was highly variable to the cultivars. Transversely sliced primary somatic embryo halves were also capable of forming secondary embryos at frequencies of up to 70% when cultured on medium containing 0.1 to 1 mg/L 2,4-D. Somatic embryos formed on zygotic embryos cultured on medium containing 0.1 to 0.2 mg/L 2,4-D had two cotyledons more frequently than one horn-type cotyledon and those on medium containing 0.5 to 4mg/L 2,4-LD had a horm-type cotyledon at a prominently higher freequency. However somatic embryos on medium containing 10mg/L or higher concentrations of 2,4-D were usually shunted at the globular stage even after transfer to medium containing lower concentrations of 2,4-D or other growth regulators. non somatic embryos with one or two cotyledons or a hem-type cotyledon were transferred to medium containing $GA_3$, those with two cotyledons converted to plantlets at a higher frequency (25%) than the others.

• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.213-219
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• 2004

Zygotic embryos were excised from immature and mature seeds of the Himalayan yew, Taxus wallichiana. The embryos germinated precociously when kept in darkness for 5 weeks and developed into full seedlings within 10-12 weeks. The highest rate of embryo germination ($81\%$) was obtained in modified Lloyd & McCown' s woody plant medium containing macro and micronutrients at half strength supplemented with $1\%$ activated charcoal, which supported both the best embryonic growth ($43\%$) and seedling development ($32\%$). However, the supplementation of basal media with kinetin, thidiazuron, 6-benzyl aminopurine or $GA_3$ had no effect on the germination of the embryos. The embryos derived from immature seeds germinated but the frequency of embryonic growth was better in mature seeds. Stratification of seeds effected precocious germination of embryos. Seeds kept at $4^{\circ}C$ for 1 week germinated earlier and at a higher frequency irrespective of the stage of seed maturity, while the germination rate declined with prolonged cold treatment for 1 month at that same temperature. Analysis of taxanes in germinating seedlings revealed that root tissues contained high levels of taxol, 10-deacetyl-baccatin ill and baccatin ill as compared to shoots. Thus embryo culture technique appears to overcome the lengthy dormancy requirement of T. wallichiana seeds.

• Korean Journal of Plant Tissue Culture
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• v.22 no.2
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• pp.77-81
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• 1995

When cultured on MS medium supplemented with 0.5 mg/L NAA alone or 1.0 mg/L 2,4-D and 0.5 mg/L BA, immature zygotic embryos of Stewartia koreana formed embryogenic calli and somatic embryos. In investigate effect of sucrose concentration on somatic embryo development, embryogenic calli were transferred to MS basal medium containing 1.5,3, 6 or 9% sucrose. The greatest frequency of somatic embryos was obtained on medium containing 6% sucrose. However addition of 1.5 or 9% sucrose to medium inhibited somatic embryo germination and development into normal plantlet After 5 weeks of hardening culture on medium containing 6% sucrose, somatic embryos were transferred to half strangth MS medium supplemented with 0.1% charcol, wherein these embryo developed into the normal plantlets.

• 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.

• Current Research on Agriculture and Life Sciences
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• v.16
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• pp.31-36
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• 1998

In order to investigate the effect of cytokinins on the cotyledonary variability of somatic embryos in Heracleum moellendorffii Hance., somatic embryos were induced from the immature zygotic embryo on MS medium containing 1.0mg/l 2, 4-D, and then transferred to 2,4-D-free and cytokinin-added medium for somatic embryogenesis after 4weeks culture. Polycotyledonary embryos were formed most abundantly(84.9%) on the 0.2mg/l BA medium as compared with the 0.2mg/l 2ip(42.6%) and kinetin(32.9%) media, and it was proportional to BA concentrations(0.01~0.1mg/l). The rate of polycotyledonary embryo formation increased proportional to the period of BA treatment and also increased more at the globular stage than at the heart, torpedo-shaped and cotyledonary stages.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.25-29
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• 2007

Plant regeneration system from zygotic embryos (2n=24) of Lilium lancifolium Thunb. via bulblet formation was estabished. Zygotic embryos of Lilium lancifolium formed bulblets and somatic embryos simultaneously when they cultured on MS medium supplemented with low concentration of 2,4-D. The highest frequency of bulblet and somatic embryo formation from zygotic embryos of Lilium lancifolium was 66.7% and 56.7%, respectively. The frequency of bulblet and somatic embryo formation was decreased when they cultured on MS medium over than 1 mg/L of 2,4-D. To regenerate whole plants, somatic embryos formed on zygotic embryos were transferred to MS basal medium. However somatic embryos did not fully converted into plantlets. Further incubation in the light, elongated somatic embryos formed numerous bulblets at the base of somatic embryos. Upon transfer to MS basal medium, bulblets were successfully converted into plantlets after further 4 weeks of culture in the light. After acclimatization, plantets from bulblets were transferred to soil and grown to normal plants in growth chamber (approximately $30\;{\mu}mol\;m^{-2}s^{-1}$, 16/8h photo period, $25^{\circ}C$) The chromosome analysis revealed that plants regenerated from zygotic embryos showed 2n=24. These results indicate that chromosome stability of source tissue is maintained during plant regeneration via bulblet formation.

• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.52-60
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• 2016

In animal reproduction, the quality of oocytes and embryos has been evaluated by the expression of specific molecules. Follistatin (FST), which was isolated from follicular fluid, binds and bio-neutralizes the TGF-${\beta}$ superfamily members. Previous studies using the bovine model showed FST could be an important molecular determinant of embryo developmental competence. However, the effect of FST treatment on porcine embryo developmental competence has not been established. In this study, the effect of exogenous FST on porcine embryo developmental competence was investigated during in vitro culture. FST (10 ng/ml) treatment induced a significant decrease in the rate of cell arrest at the 4-cell stage. The expression levels of DNA-methyltransferase 1 (DNMT1), histone deacetylase 1 (HDAC1), and histone deacetylase 2 (HDAC2) were decreased in 4-cell stage embryos. FST treatment also resulted in significant improvements in developmental competence of embryos in terms of blastocyst formation rate and OCT-4 mRNA levels, the latter being related to pluripotency. In conclusion, during in vitro culture, FST treatment significantly ameliorated 4-cell block during embryonic development and improved embryo developmental competence. Therefore, FST treatment may potentially have a functional role in porcine embryogenesis that is broadly applicable to enhance in vitro embryo development.

• Korean Journal of Plant Tissue Culture
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• v.27 no.4
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• pp.245-258
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• 2000

Somatic embryogenesis has become a major tool in the study of plant embryology, as it is possible in culture to manipulate cells of many plant species to produce somatic embryos in a process that is remarkably similar to zygotic embryogenesis. Traditionally, the process has been studied by an examination of the ex vitro factors which influence embryo formation. Later structural, physiological and biochemical approaches have been applied. Host recently, molecular tools are being used. Together, these various approaches are giving valuable information on the process. This article gives an overview of somatic embryogenesis by reviewing information on the morphogenesis, physiology, biochemistry and molecular biology of the process. Topics covered include a brief description of the factors involved in the production of embryogenic cells. Carrot cell suspension is most commonly used, and the development of a high frequency and synchronous system is outlined. At the physiological and biochemical lev-els various topics, including the reactivation of the cell cycle, changes in endogenous growth regulators, amino acid, polyamine, DNA, RNA and protein metabolism, and embryogenic factors in conditioned medium are all discussed. Lastly, recent information on genes and molecular markers of the embryogenic process are outlined. Somatic embryogenesis, the best example of totipotency in plant cells, is not only an important tool in studies in basic biology, but is potentially of equal significance in the micropropagation of economically important plants.

• Journal of Ginseng Research
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• v.23 no.3 s.55
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• pp.148-163
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• 1999

The efficacy of three auxins, viz. 2,4-0, NAA and dicamba, were compared for the induction of somatic embryogenesis in American ginseng (Panax quinquefolium L.). Somatic embryos (SEs) formed on ginseng cotyledonary, zygotic embryo and shoot explants after 8 weeks of induction by the auxin stimuli. Significantly more somatic embryos were induced by culture of any of the ginseng explants on media supplemented with $5{\mu}M$ 2,4-0 than any other auxin treatment. Shoots derived from somatic embryos had the greatest regenerative potential and zygotic embryos the least. Explants generated from green (unstratified) seeds gave similar or higher frequency of embryogenesis as the explants derived from stratified seeds. Histological and SEM studies confirmed that the regenerimts were somatic embryos. Somatic embryos germinated and developed into normal plants in $3\~6$ months. About $10\%$ of plantlets from second generation SEs formed flowers within 10 weeks, particularly on media supplemented with $GA_3$ The development of a regeneration system for ginseng through somatic embryogenesis is a necessary first step for mass propagation and genetic improvement of American ginseng.

• Korean Journal of Plant Resources
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• v.17 no.3
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• pp.272-277
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• 2004

Zygotic embryos of Stewartia korean Nakai were cultured to determine the effects both of BA and NAA on adventitious shoot induction. Multiple shoots (about 11 per explant) were formed when the embryos were treated with 1.0 mg/L BA alone. On the other hand, NAA appeared to inhibit shoot induction when treated with BA. Adventitious shoots looked differ in form and color by the combinations of BA and NAA treated. When both BA and NAA were present, the shoots became short and developed dark color. The highest rooting was observed at 0.5mg/L NAA. The results could be useful for the establishment of in vitro regeneration system for Stewartia koreana Nakai.