• 식물조직배양학회지
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• 제27권4호
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• pp.299-307
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• 2000

A large amount of information is currently available for somatic embryogenesis of plants. However, one common problem related to somatic embryos is that the conversion rate can be low for some species. Apical meristems are responsible for post-embryonic growth of the embryo. The low percentage observed is most likely a result of poor apical meristem development or defects in the meristem organization during somatic embryogenesis. In flowering plants, apical meristems are well developed by the late heart stage of zygotic embryo development. In conifers, such as white spruce, apical meristems are formed at the pre-cotyledon stage. Thus, apical meristem development occurs very early, prior to the maturation stage of embryo development. Once formed, meristems are stably determined. In the somatic embryo, as exemplified by white spruce, since embryo development is not synchronous, tissue differentiation including apical meristem formation occurs throughout the“maturation”stage. Different apical meristem organizations can be found among different individuals within a population. In contrast to their zygotic counterparts, the apical meristems appear not to be stably determined as their organization, as the shoot apical meristem especially, can be easily modified or disrupted. Precocious germination seldom results in functional plantlets. All these observations suggest that the conditions for somatic embryo maturation have not been optimized or are not suitable for meristem formation and development. The following strategies could improve meristem development and hence conversion: 1. Simulate in ouuio conditions to promote meristem development prior to the“maturation”treatment.2. Prevent deterioration of apical meristem organization during somatic embryo maturation.3. Promote further meristem development during embryo germination.

• 식물조직배양학회지
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• 제28권3호
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• pp.129-134
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• 2001

Winter bud explants from 15 individual angelica tree (Aralia elata) were cultured in vitro to find out optimal conditions for somatic embryo induction as well as plant regeneration. Calli are induced and grown on MS medium supplemented with 1.0 mg/L 2,4-D for 4 weeks and subcultured on a half-strength MS medium without phytohormones to induce somatic embryos. Inter-simple sequence repeat (I-SSR) markers were analyzed with total DNAs extracted from the trees. Genotype effects on somatic embryo induction were examined by cluster analysis. Callus induction rate varied from 58.5 to 100% among the genotypes. Somatic embryo induction rate also greatly varied from 0 to 100% among the genotypes. There was a significant difference in somatic embryo induction rate even among the individual trees that showed close genetic relationships each other. This suggested that somatic embryo induction rate in Aralia elata be influenced by a few major specific genes rather than whole genomic similarity among individual trees. Four individuals of Ulneong-7, Cheju-1, Shingu and China, which are recalcitrant to somatic embryo induction, turned out to have a close genetic relationship, suggesting that both physiological and genetic factors affect somatic embryo induction. The results suggest that genotype selection be the most important factor to achieve an efficient propagation, although cultural optimization through medium and explant manipulation may also play crucial roles in somatic embryogensis as well as plant regeneration of these species.

• Plant Biotechnology Reports
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• 제2권2호
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• pp.153-161
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• 2008

The factors influencing somatic embryo maturation, high frequency somatic embryo germination, and plantlet formation were studied in Terminalia chebula Retz. Maturation of somatic embryo were influenced by a number of factors such as in vitro culture passage, concentrations of sucrose, levels of abscisic acid (ABA), basal media and media additive combinations. Maximum frequency of somatic embryo maturation ($57.22{\pm}2.02$), was obtained on MS medium supplemented with 50 g/l sucrose. Different factors such as strengths of MS nutrients, plant growth regulators, media additives and their combinations controlling somatic embryo germination and plantlet formation were studied. High frequency of germination and plantlet formation ($58.80{\pm}1.47$) were achieved by subsequent subculture of mature somatic embryos on MS medium containing 30 g/l sucrose and 0.5 mg/l benzyl-adenine (BA). However, although duration of in vitro passage of the callus tissue was critical, contribution of the combinations of plant growth regulators and media additives showed nugatory effect on somatic embryo maturation and germination as evident from variable responses.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
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• pp.85-89
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• 1999

Somatic embryogendesis is one of good examples of the basic research for plant embryo development as well as an important technique for plant biotechnology. This paper describes the direct somatic embryogenesis from zygotic embryos of Panax ginseng is reversely related to normal axis growth of zygotic embryos by the experiment of various chemical treatments. Under the normal growth condition, the apical tips of embryo axis produced an agar-diffusible substance, which suppressed somatic embryo development from cotyledons. Although the cells of zygotic embryos were released from the restraint of embryo axis, various factors were still involved for somatic embryo development. Electron microscopic observation revealed that the ultrastructure of cells of cotyledon epidermis markedly changed before initiation of embryonic cell division, probably indicating reprogramming events into the cells embryogenically determined state. Polar accumulation of endogenous auxin or cell-cell isolation by plasmolysis pre-treatment is the strong inducer for the somatic embryo development. The cells for the process of somatic embryogenesis might be determined by the physiological conditions fo explants and medium compositions. Direct somatic embryos from cotyledons fo ginseng were originated eithrer from single or multiple cells. The different cellular origin of somatic embryos was originated either from single or multiple cell. The different cellular origin of somatic embryos was depended on various developmental stages of cotyledons. Immature meristematic cotyledons produced multiple cell-derived somatic embryos, which developed into multiple embryos. While fully mature cotyledons produced single cell-derived single embryos with independent state. Plasmolysis pretreatment of cotyledons strongly enhanced single cell-derived somatic embryogenesis. Single embryos were converted into normal plantlets with shoot and roots, while multiple embryos were converted into only multiple shoots. GA3 or a chilling treatment was prerequisite for germination and plant conversion. Low concentration of ammonium ion in medium was necessary for balanced growth of root and shoot of plantlets. Therefore, using above procedures, successful plant regeneration of ginseng was accomplished through direct single embryogenesis, which makes it possible to produce genetically transformed ginseng efficently.

• Journal of Plant Biotechnology
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• 제7권3호
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• pp.187-193
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• 2005

A protocol was developed for somatic embryogenesis with 100% induction rate from immature zygotic embryo axes of peanut (Arachis hypogaea L. cv. DRG-12) cultured on MS medium containing $18.09\;{\mu}M$ 2,4-D. The frequency of somatic embryogenesis (31.7%) as well as the number of somatic embryos induced per explant (6.6) decreased when the concentration of 2,4-D was increased to $72.4\;{\mu}M$. Morphologically abnormal somatic embryos were observed at a frequency of 43.3% on MS medium containing $72.4\;{\mu}M$ 2,4-D. Somatic embryos isolated from 30-day-old cultures of immature zygotic embryo axes exhibited precocious germination with varied responses when placed on MS basal medium with 3% sucrose. Maximum shoot induction (80.0%) was observed from somatic embryos isolated from 60-day-old cultures of immature zygotic embryo axes when placed as a clump rather than individually on MS medium supplemented with $26.63\;{\mu}M$ BA and $0.54\;{\mu}M$ NAA. Shoots developed from somatic embryos rooted with higher frequency (93.3%) on Blaydes' medium containing $5.4\;{\mu}M$ NAA.

• 한국자원식물학회지
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• 제12권2호
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• pp.133-138
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• 1999

당근(Daucus carota L. cv. Hongshim)의 접합자배와 체세포배의 경정부의 구조는 주사전자현미경과 종단면 관찰을 통하여 이루어졌다. 접합자배의 경정부는 도립된 보우트형이고, 2ㆍ3ㆍ4자엽 체세포배의 경정부는 각각 도립된 보우트형, 피라미드형 및 볼록한 다이아몬드형으로 나타났다. 접합자배의 경정부는 다소 작은 세포들로 구성되어 있고, 초층과 내체의 구별이 된다. 체세포배의 경정부는 다소 큰 세포들이 불규칙하게 배열되어 있다.

• 한국약용작물학회지
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• 제8권1호
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• pp.14-20
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• 2000

인삼조직배양에서 배양환경 조절방법의 필요성을 검토코자 생장조절물질 IBA, BA, GA 각 $3mg/\;{\ell}$ 첨가한 MS 배지에 $CO_2(2500ppm)$를 강제 통기방식에 의해 기내에 처리하여 기관분화 유형별로 특성을 조사하였던 바 결과를 요약하면 다음과 같다. 저장종자의 분화능은 저온처리 60일 종자에서 적출한 배에 비하여 80일정도 저온처리한 성숙된 배의 자엽조직이 양호하였다. 기관발생 유형에서 $CO_2$처리 효과는 부정아 형성보다 shoot primordium 의 생장과 발달에 현저한 효과가 있었고 1개의 배로부터 shoot primordium 을 통해 수백 개의 신초분화가 가능하였다. 배발생 유형에서 $CO_2$처리는 무처리에 비해 indirect somatic embryo 분화 모두에 효과가 있었다. Indirect somatic embryo는 대체로 유관속 중심주와 상배축이 미분화된 관계로 신초가 분화 생장하지 못하였다. 그리고 direct somatic embryo는 자엽 이변의 하단부에서 분화 발달하였고 지상부와 지하부 그리고 잠아를 갖는 완전한 식물체로 생장하였다.

• 식물조직배양학회지
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• 제22권5호
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• pp.291-298
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• 1995

시호(Bupleurum falcatum L.)의 잎절편으로부터 체세포배형성을 통한 식물체 재생과 체세포배 발생의 이상을 일으키는 2,4-D의 영향에 대하여 또한 체세포배의 자엽수와 발아와의 관계에 대하여 기술하였다. 배발생능 캘러스는 1mg/L 2,4-D가 첨가된 MS 고형기본배지에서 배양된 캘러스로부터 선발하였다. 2,4-D 첨가 MS 기본배지에서 6주간 배양후 3주간 2,4-D가 제거된 배지에서 배양하여 체세포배 발생과 비정상적인 체세포배의 자엽발생을 관찰하였다. 이상자엽의 빈도는 정상인 2개 자엽에서 65% 인데 비하여 1개의 자엽에서 7%, 3개의 자엽을 갖는 체세포배에서는 25%, 4개 자엽에서는 5%, 5개 자엽에서 2% 및 나팔형 자엽배는 3% 이었다. 2개의 정상적인 자엽을 갖는 체세포배의 발아율이 80%인 것에 비하여 1, 3 4, 5개의 자엽을 갖는 체세포배에서는 25%, 58%, 38% 및 20%로 발아율이 낮았다. 그러나 나팔형의 비정상 체세포배는 전혀 발아되지 않았다. 다자엽배의 구조는 체세포배의 뿌리 또는 배축에서 원통상전형성층을 나타내었지만 자엽절에서는 자엽수와 동일한수의 전형성층속으로 분포되었다. 체세포배의 자엽수 변이는 전형성층의 수와 밀접한 관계가 있다.

• 한국동물생명공학회지
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• 제37권4호
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• pp.213-217
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• 2022

Haploidization in somatic cells is the process of reducing the diploid somatic chromosomes to haploid. Several studies have attempted somatic haploidization using oocytes in mice and humans. Some researchers showed partial somatic haploidization, but none observed embryo development. Our study attempted somatic haploidization using the modified somatic nuclear transfer (SCNT) protocol with various combinations of chemicals or proteins in mice. This study induced the proper segregation of somatic homologous chromosomes and full embryo development in vitro. Furthermore, somatic haploid embryos established embryonic stem cells and produced live births. The current review summarizes this recent study on the success of somatic haploidization and provides an overview of other related studies on somatic haploidization.

• Plant Biotechnology Reports
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• 제4권4호
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• pp.303-309
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• 2010

Endoreduplication is a developmental process that is unique to plants and occurs in all plants. The present study aimed to assess endoreduplication in various explant tissues and regenerated somatic embryos of Doritaenopsis. We further investigated the effects of light quality on endoreduplication and somatic embryo proliferation. To this end, we studied endoreduplication in leaves and root tips from regenerated plantlets and somatic embryos and in developing somatic embryos under 4 types of lighting conditions: red light, red + far-red light, red + blue light, and white light. We found that the degree of endoreduplication varied in different explants, and that the choice of explants used also influenced the ploidy levels of the newly regenerated somatic embryos. The DNA content of the leaf (2C-8C) was less than that of the root tip (2C-16C) and somatic embryo (2C-64C). In terms of light quality, the combination of red and far-red light produced the highest number of somatic embryos, while maintaining a low degree of endoreduplication. The data obtained indicate that this light combination stimulates somatic embryogenesis in Doritaenopsis and may exert some control on endoreduplication during cell division. These findings can be applied to achieve a reduction in somaclonal variations for the purpose of mass proliferation and genetic improvement.