• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.51-56
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• 1998

This study was carried out in order to establish plant regeneration via somatic embryogenesis from leaf explant of Ostericum koreanum Kitagawa and to elucidate the effects of NAA and cytokinins (kinetin, BA) on the abnormalities of somatic embryo and the relationship between thecotyledon numberand germinability. Calli were formed on leaf explants cultured on MS agar medium supplemented with various concentrations (0, 0.1, 0.5, 1, 2 mg/L) of NAA and cytokinins. The calli were white, watery and soft, became browning during cultures. Somatic embryos were formed from pale yellowish calli derived browning calli. High frequency somatic embryos were observed on MS medium containing 1 mg/L NAA and 0.1 mg/L BA after 60 days of culture. The mature somatic embryos germinated into plantlets without subculture after 2 weeks. The frequency of normal somatic embryo with two cotyledons was 39.8%. On the other hand, cotyledonary abnormalities of somatic embryos were observed at considerable frequency: 33.6% of somatic embryo with one cotyledon, 15.3% cotyledons with three, 8.2% four cotyledons and 3.1% jar shaped cotyledon. Germination frequency of somatic embryos with two cotyledons was 97.4%, and that of the embryos with abnormal cotyledon was almost similar to that of embryos with two cotyledons, except jar shaped somatic embryos (33.3%).

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.1-5
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• 1998

This study describes the effect of the growth regulators such as 2,L-D and BA, on the structural abnormalities of somatic embryos derived from leaf explants of Angelica gigas Nakai, Also, the relationship between the cotyledon number of a somatic embryo and its germinability is explored. Embryogenic calli were selected from calli formed on explants cultured on MS solid basal medium supplemented with 0.5mg/L 2,4-D, 1mg/L 2,4-D, 1mg/L plus 0.1mg/L BA, and 1 mg/L 2,4-D plus 0.5mg/L BA. Cotyledonary abnormalities were observed in somatic embryos which were developed from embryogenic calli cultured on MS medium containing 1mg/L 2,4-D for 8 weeks and then subcultured on 2,4-D free MS medium for 3 weeks. The frequency of abnormalities was as follows: 22.8% one cotyledon, 42.5% two cotyledons, 16.8% three cotyledons, 7.8% four cotyledons, 1.8% five cotyledons, and 8.2% jar shaped cotyledon. In addition, ABA treatment indicated an improvement of the somatic embryo with normal cotyledon (65.3%). ABA was important role to the high production of normal somatic embryos. Two cotyledon embryos showed germinability 77.8%. However the germinability of somatic embryos with anomalous cotyledons was prominently low: One cotyledon, 62.5%; three cotyledons, 43.3%; four cotyledons, 60%; five cotyledons, 50% and jar shaped cotyledon, zero%. Thus, germinability was essentially, inversely proportional to cotyledon number.

• Journal of Plant Biotechnology
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• v.33 no.4
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• pp.297-302
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• 2006

In general, the proliferation of orchids via somatic embryos has been used for mass production of somatic clones because of high propagation efficiency. In spite of high propagation rate, this method often brings somaclonal variation, especially polyploid frequency. Therefor we here concentrated to investigate the relationship between endopolyploidization patterns of explants and the occurrence of tetraploid variant in clonally proliferated Doritaenopsis via somatic embryo regeneration system. In the fully developed somatic embryo, upper part contained 2C to 16C while middle and lower parts showed 2C to 32C DNA content. Two-week-old embryo contained 2C to 16C, whereas those regenerated after 4 to 10-week-old contained 2C to 64C nuclei. Results showed that endoreduplication was variable depending upon tissue types, ages, and parts in one species. lower part of somatic embryo having high endoreduplication degree increased the regeneration of tetraploid variants by about 3-fold comparing to upper part of somatic embryo culture. polyploid frequency occurrence might be closely related to the high levels of endoreduplication of somatic embryos used as explant. It suggested that the upper part of somatic embryo having comparatively low endoreduplication degree is suitable for the stable in vitro propagation system.

• 산림경영
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• s.143
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• pp.46-48
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• 2000

산림청 임업연구원(원장 노의래)은 최근 침엽수종인 소나무, 낙엽송 및 리기테다소나무 등 체세포배에 의한 복제 묘목을 대량생산하는 생물공학적 기술을 개발하는데 성공하였다. 지금까지 임업에서는 접목이나 꺾꽂이 등의 무성증식방법으로 특정형질을 가진 복제묘목을 생산하여 왔다. 특히 이러한 방법은 유실수, 포플러 등에 오랫동안 적용되어 왔으나 최근에는 체세포배에 의한 복제기술이 주로 활엽수 등에서 성공한 바 있다. 이번에 개발한 체세포배에 의한 복제기술은 내년부터 솔잎혹파리에 강한 내충성 소나무, 형질이 월등히 우수한 낙엽송 및 리기테다소나무의 대량생산에 적용하여 단기간내에 솔잎혹파리 내충성 소나무 복제묘목을 보급함으로써 솔잎혹파리 피해가 없는 우량소나무 조림이 가능할 것으로 기대하고 있다. 현재 캐나다 및 뉴질랜드와 같은 임업 선진국가에서는 체세포배에 의한 복제기술을 이용하여 새로운 우수 품종을 산업적인 규모로 대량 생산하고 있으나, 우리나라 소나무와 같이 2엽송(二葉松)인 경우 체세포배에 의한 복제 식물체를 생산한 것은 세계적으로 드문 일이다. 이번 연구 결과는 유전자조작 등의 첨단 생물공학 기법을 나무에 적용하기 위한 필수적인 전(前)단계로서 침엽수 육종에서 새로운 전기를 마련하였다고 볼 수 있으며 특히 임업도 농작물과 같이 특수한 품종을 육성할 수 있는 길을 터놓아 산림자원화와 산주소득증대에 크게 기여할 수 있을 것이다.

• Korean Journal of Plant Tissue Culture
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• v.21 no.3
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• pp.177-182
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• 1994

Cotyledon segments of korean ginseng produced somatic embryos when cultured on MS basal medium, whereas plumule or excised axis explants did not. histological examination revealed that the cells in proximal region of cotyledon turned meristematic and densely cytoplasmic was composed of smaller and more densely cytiplasmic cells than the subepidermal cells. however, in the case both epidermis and subepidermal cells were almost the same in size and cytoplasmic density, the embryo originated from multiple cells.

• KSBB Journal
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• v.11 no.1
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• pp.107-114
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• 1996

The enhancing effect of excreted cell factors on the production of somatic embryos from suspension cultures of Daucus carota was studied as a function of factors including molecular size, harvesting time, injection period, and concentration of the extracellular compounds. The production of late-stage embryos was increased up to 1, 500 embryos/ml compared with control cultures when high molecular size and extracellular factors, extracted from newly established embryo culture at early stationary phase, were added at the starting time. The stimulating effect on the production of somatic embryos can be attributed to the presence of high molecular size(> 10 kDa) compounds.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.137-142
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• 2000

Calli were induced from the explants of infloresence, petiole and leaf blade of Cnidium officinale on MS medium with 2.4-D, while embryogenic callus was induced only from inflorescence explants. Somatic embryos of 78 per explant were formed during subculture of the explants on medium without 2.4-D after culture on medium with 2 mg/L 2.4-D. Cotyledonary variation, cup-shaped cotyledon of 49% and other abnormal cotyledons of 13.5 % was observed on the somatic embryos. However this variation could be overcomed by the addition of activated charcoal onto culture medium. Somatic embryos at cotyledonary stage germinated on MS basal medium but the germination rate was very poor, blow 50 %. Somatic embryos on the medium with activated charcoal showed improved germinaton.

• Korean Journal of Plant Tissue Culture
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• v.21 no.5
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• pp.299-302
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• 1994

Immature zygotic embryos (up to 4mm in length) were cultured on MS medium supplemented with 0.5 to 8mg/L 2,4-D. Up to 87% of them formed somatic embryos on the plumule without producing an intervening callus. The site of somatic embryo formation was confirmed by culturing plumule explants, which consisted of shoot apical meristem domes with 1 or 2 leaf primordia excised from 2-week-old seedlings. When the concentration of 2,4-D was increased over 4 mg/L, the plumule explants produced nonembryogenic calli only, whereas the distal end of the cotyledons directly formed numerous somatic embryos at frequencies of up to 60%. Upon transfer onto MS basal medium,2 out of 15 somatic embryos converted into plantlets. The plantlets were potted to a soil mixture and grown to maturity in a phytotron.

• Journal of Plant Biotechnology
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• v.47 no.2
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• pp.179-184
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• 2020

Embryogenic calli from Codonopsis lanceolata L. were cultured in MS liquid media and supplemented with various concentrations of primary carbon sources to study the effects of carbohydrates and osmoticum on somatic embryogenesis and somatic embryo morphology. Sucrose, glucose, and a combination of 3% sucrose and various concentrations of sorbitol or mannitol as osmoticum were used as carbon supplements. The maximum number of somatic embryos per flask was greater in media exclusively supplemented with 3% sucrose (128.29) than exclusively glucose-supplemented media (47.67) and either supplement combination of 3% sucrose and osmoticum (95.67 with mannitol and 114.00 with sorbitol). The number of somatic embryos gradually decreased in media with increasing concentrations of combined osmoticum supplement. Decreases also occurred in the highest concentrations of sucrose- and glucose-supplemented media. The total frequency of somatic embryos with two cotyledons was slightly higher in medium with 3% + mannitol (24.09%) compared with exclusively sucrose (21.52%), glucose (21.22%), or 3% sucrose + sorbitol (22.13%). As concentrations of sucrose and glucose increased, the occurrence of two cotyledons and trumpet cotyledons gradually decreased and the occurrence of polycotyledon and globular stage embryos increased. Furthermore, as concentrations of 3% sucrose and osmoticum increased, the occurrence of trumpet cotyledon and globular stage embryos increased and the occurrence of polycotyledon gradually decreased. These results demonstrated that the somatic embryogenesis and occurrence of cotyledon morphology were influenced by the concentration of carbohydrates and combinations of 3% sucrose and osmoticum supplements.

• Journal of Plant Biotechnology
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• v.40 no.1
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• pp.55-58
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• 2013

Immature embryos of Glycine max L. was cultured on Murashige and Skoog's (MS) medium supplemented with 1 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D). After 6 to 8 weeks of culture, immature embryos produced somatic embryos. Of somatic embryos, two cotyledonary embryo (14%), one cotyledonary embryo (37%), fused cotyledonary embryo (43%), and stunted globular embryos (6%) were observed. The procambial strand of cotyledons originated from circular procambial tissues of lower hypocotyl. The circular procambial tissues were independently divided into one or two procambial strand at the edge of cotyledonary-node, and then connected to each cotyledon to form somatic embryos with one or two cotyledons. When cotyledon was a fused type, the circular procambial strand in lower hypocotyl was continuously connected to the cotyledon. Also, somatic embryos with two cotyledons developed a functional shoot apex with the tunica-corpus structure. In contrast, somatic embryos with one or fused cotyledon formed an abnormal shoot apex without the tunica-corpus structure or with non-dome shape in the inter-cotyledonary area. These results indicated that the variation of cotyledon in somatic embryos is closely related to procambial differentiation and shoot apical meristem development.