• 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 Biology
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• v.39 no.1
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• pp.71-77
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• 1996

Embryogenic callus was selected from callus induced from hypocotyl segment cultures of Daucus carota seedlings on MS basal medium supplemented with 1.0 mg/L 2,4-D. Cell clumps prepared from the embryogenic callus were transferred to MS medium without 2,4-D for somatic embryo development. Cotyledonary abnormalities were frequently observed on somatic embryos developed after the incubation of cell clumps in MS basal medium with 1.0 mg/L 2,4-D for one week and then subculture in the same medium but without 2.4-D for two weeks. The percentage of abnormalities was as follows: 5% one cotyledon, 21% three cotyledons, 6% four cotyledons, 5% five cotyledons, 0.2% six cotyledons and 1% trumpet-like cotyledons. On the other hand, the normal somatic embryo with two cotyledons appeared at 63%. The germination rate of somatic embryos was higher in two cotyledon somatic embryos than in multicotyledonary embryos. Trumpet-like somatic embryos did not germinate normally showing limited elongation and enlargement of roots and cotyledons without shoot development. From anatomical examination circular procambium in the root of somatic embryo began to branch around the middle regions of the hypocotyl which extended into the cotyledons through the cotyledonary nodes and the number of branched procambial strands in hypocotyl was equal to the number of cotyledons. Monocotyledonous somatic embryo always had larger cotyledon than that of somatic embryos with multicotyledons and had horseshoe-like cotyledons where the procambium was of the same structure.ucture.

• Korean Journal of Plant Tissue Culture
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• v.22 no.5
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• pp.291-298
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• 1995

This study describes plant regeneration from leaf explant of Bupleurum falcatum through somatic embryogenesis, and the effect of 2,4-dichlorophenoxyacetic acid on somatic embryo abnormalities. The relationship between the cotyledon number of somatic embryo and its germinability is also described. Embryogenic calli were selected from calli formed on explants cultured on MS solid basal medium supplemented with 1 mg/L 2,4-D. Cotyledonary abnormalities were observed in somatic embryos which were developed from calli cultured on MS medium with 1 mg/L 2,4-D for 6-week and then subcultured on 2,4-D free MS medium for 3 weeks. The frequency of abnormalities was as follows: 7% of somatic embryos had one cotyledon, 65% of them had two cotyledons, 25% three cotyledons, 5% four cotyledons, 2% five cotyledons, and 3% trumpet-like cotyledons. The two cotyledon somatic embryos were germinated at a frequency of 80%. However the germination frequency of one cotyledon embryo and multicotyledonary embryo was lower than that of the two cotyledon somatic embryo. All of trumper-like somatic embryos did not germinate. Histological observations of multicotyledon embryo showed circular procambium in the root but pocambial strands in the cotyledonary node or upper hypocotyl. The number of the strands was equal to the cotyledon number.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.4
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• pp.297-302
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• 1999

Cotyledonary abnormalities were observed in secondary somatic embryos which were developed from calli cultured on MS medium with various concentrations of 2,4-D. In MS medium containing hormone-free or $0.1mg/{\ell}$ 2,4-D, the frequency of normal embryo formation with two cotyledons were above 57%. According to concentration of 2,4-D increment the frequency of normal embryos were decreased. In MS medium containing $4mg/{\ell}$ 2,4-D, the frequency of normal embryo formation was just 10%. The rate of germination was as follows; 37.7% of somatic embryos had one cotyledon, 85% two cotyledons, 38% three cotyledons, 35% four cotyledons, 25% five cotyledons and 29% trumpet-like cotyledons. About 80% of the embryos with two cotyledons were converted into normal plants, but one, three or four cotyledons were only 6.8~10%. The five or trumpet-like embryos were not developed into normal plants.