• 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.27 no.3
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• pp.227-232
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• 2000

This study was carried out to elucidate the effect of cadmium on somatic embryogenesis and plant regeneration from cultured cells of Daucus carota L. Embryogenic calli were induced from cotyledon explants of carrot seedlings cultured on MS solid medium supplemente with 1 mg/L 2,4-D Embryogenic cells proliferated on medium supplemented with 1 mg/L 2,4-D were also cultured in liquid MS medium containing various concentrations (50, 100, 200, 500, 1000 $\mu$M) of cadmium for one week and then transferred to MS basal medium. Somatic embryogenesis occurred in suspension culture treated with 50 $\mu$M and 100 $\mu$M cadmium or untreated with cadmium. When cadmium was treated in suspension culture, production of two and four cotyledonary somatic embryos was reduced, but that of three cotyledonary somatic embryo was increased. Two cotyledonary embryos showed higher regeneration frequency than abnormal somatic embryo with one, three and four cotyledon. Regardless of cotyledonary variation, germination frequency of somatic embryos treated with cadmium was decreased in compared with that of embryos in basal medium.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.69-72
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• 2004

Somaclonal variation, defined as phenotypic and genetic variations among regenerated plants from a parental plant, could be caused by changes in chromosome structure, single gene mutation, cytoplasm genetic mutation, insertion of transposable elements, and DNA methylation during plant regeneration. The objective of this study was to evaluate DNA variations among somaclonal variants from the cotyledonary node culture in soybean. A total of 61 soybean somaclones including seven $\textrm{R}_1$ lines and seven $\textrm{R}_2$ lines from Iksannamulkong as well as 27 $\textrm{R}_1$ lines and 20 $\textrm{R}_2$ lines from Jinju 1 were regenerated by organogenesis from the soybean cotyledonary node culture system. Field evaluation revealed no phenotypic difference in major agronomic traits between somaclonal variants and their wild types. AFLP and SSR analyses were performed to detect variations at the DNA level among somaclonal variants of two varieties. Based on AFLP analysis using 36 primer sets, 17 of 892 bands were polymorphic between Iksannamulkong and its somaclonal variants and 11 of 887 bands were polymorphic between Jinju 1 and its somaclonal variants, indicating the presence of DNA sequence change during plant regeneration. Using 36 SSR markers, two polymorphic SSR markers were detected between Iksannamulkong and its somaclonal variants. Sequence comparison amplified with the primers flanking Satt545 showed four additional stretches of ATT repeat in the variant. This suggests that variation at the DNA level between somaclonal variants and their wild types could provide basis for inducing mutation via plant regeneration and broadening crop genetic diversity.

• 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.

• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.511-515
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• 2013

Hypocotyls explants of melon seedling were cultured on Murashige and Skoog's (MS) medium supplemented with 1 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5 mg/L benzyl aminopurine (BA) for 6 weeks to produce somatic embryos. In somatic embryos produced through intervening bright yellow friable (BYF) from the explants, somatic embryos with two-cotyledon (26%) and horn-type cotyledon (74%) were observed. The procambial strand of cotyledons was originated from circular procambial tissues of lower hypocotyls. The circular procambial independently divided into two procambial strand at the edge of cotyledonary-node, and then connected to each cotyledon to form somatic embryos with two-cotyledon. When cotyledon was horn-type, the circular procambial strand in lower hypocotyls would continuously remain connected to the cotyledon. However, somatic embryos with two or horn type cotyledon formed an abnormal shoot apex without the tunica-corpus structure or dome shape in the inter-cotyledonary area. These results demonstrated that the variation of cotyledon in somatic embryos was closely related to procambial tissue differentiation and shoot apical formation.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.165-168
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• 1995

The embryos formed from anther culture of peony exhibited divergent morphologies. The frequency of normal embryos with two cotyledons was about two times higher in the embryos formed through direct embryogenesis than those formed from callus. About 69% of the embryos with two cotyledons converted into normal plants, but convention rate of the abnormal embryos with one and three or four cotyledons was only 4 to 9%. The embryos of hem and bowling pin shape did not undergo development into normal plants.

• Journal of Plant Biotechnology
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• v.36 no.2
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• pp.137-143
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• 2009

An efficient system for high frequency plant regeneration was established through investigating various factors such as plant growth regulator combinations, explant types and ages, and addition of $AgNO_3$ influenced on shoot regeneration in Brassica juncea L. cv. BARI sarisha-10. Murashige and Skoog (MS) medium supplemented with 0.1 mg/L NAA (1-naphthaleneacetic acid) and 1 mg/L BA (6-benzyladenine) showed the maximum shoot regeneration frequency (56.67%) among the different combinations of NAA and BA. Explant type, explant age, and addition of $AgNO_3$ also significantly affected shoot regeneration. Of the four type of explants (cotyledon, hypocotyl, root, and leaf explants)- cotyledon explants produced the highest shoot regeneration frequency and hypocotyls explants produced the highest number of shoots per explant, whereas root explants did not produce any shoot. The cotyledonary explants from Four-day-old seedlings showed the maximum shoot regeneration frequency and number of shoots per explant. Shoot regeneration frequency increased significantly by adding $AgNO_3$ to the medium. Two mg/L $AgNO_3$ appeared to be the best for shoot regeneration with the highest shoot regeneration frequency (86.67%) and number of shoots per explant (7.5 shoots). Considerable variation in shoot regeneration from cotyledonay explants was observed within the B. juncea L. genotypes. The shoot regeneration frequency ranged from 47.78% for cv. Shambol to 91.11% for cv. Rai-5. In terms of the number of shoots produced per explant, B. juncea L. cv. Daulot showed the maximum efficiency. MS medium supplemented with 0.1 mg/L NAA showed the highest frequency of rooting. The regenerated plantlets were transferred to pot soil and grown to maturity in the greenhouse. All plants were fertile and morphologically identical with the source plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.173-177
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• 1996

This study was carried out to improve utility value as soybean genetic resources and to obtain basic information for color-soybean breeding. The 146 local color soybean lines collected in Kyongbuk province were investigated major agronomic characteristics. Seed coat-color showed seven different types which were black, white mottled on black, white mottled on brown, black saddle on green, green, raddish brown and brown. Major color types were black and green colors. The 90 percent of collected lines were purple in flower color. The 86 lines were green in color of cotyledonary part and 64 lines yellow. Great variations were observed in days to flowering and days from flowering to maturity, 51 to 81 days and 75 to 103 days, respectively. But days to maturity was 150 to 159 days and had smaller variation than days to flowering and days from flowering to maturity in all lines except those with white mottled on black (123 days). The 100 seed weight ranged below 10g to over 36g. Black seed color with green embryo seed was heavier seed weight than black seed color with yellow embryo seed. Seed shape of all collected lines was ellipsodial and average ratio of length: width: thickness of seed was 1:0.87:0.69. Positive correlation coeffieients were obtained among seed length, width, thickness and 100 seed weight.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.244-249
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• 1988

Some experiments were conducted to utilize the raphanus test as a bioassay method for plant growth regulaters and hormonal herbicides. Among seven radish cultivars, the response of Jangbaegminong was the most sensitive and quantitative to ${\alpha}$-NAA and its coefficient of variation value was the lowest. The optimum application time of test compounds was estimated seven to nine days after seeding. After ${\alpha}$-NAA treatment the curvature angle of radish cotyledonary petiols was sharply increased to the maximum value at 24 hours after and was changed by light and temperature conditions. The curvature response was observed by application of ${\alpha}$-NAA, phenoxy and indole compounds but often plant growth regulators, $GA_3$ benzyladenine, ABA and homobrassinolide was not detected by this method. So this bioassay was useful to evaluate the activity of a compound as an auxin or a hormonal herbicide.