• 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.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.119-124
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• 1997

Plantlets were regenerated from various explants (shoot tip, leaf blade, petiole and root segments) via organogenesis and/or somatic embryogenesis from Armoracia rusticana(Lam) Gaerth., Mey, et Scherb.. Shoot regeneration rate from callus was highest on the MS mediums supplemented with 0.5 ㎎/L IAA, 5.0㎎/L BA and 10.0㎎/L spermine. A Low frequency of regeneration occurred on hormone-free MS medium. Multiple shooks were regenerated at a pH of 4.0 to 8.0 on MS medium supplemented with 1.0 ㎎/L BA and 0.1 ㎎/L NAA. Polyamines promoted shoot- and root-formation by 2 to 4 times normal, Specific proteins associated with organogenesis were identified. Somatic embryogenesis occurred directly from the leaf blade, petiole and root segments cultured on MS medium with 2.0 ㎎/L BA and 2.0 ㎎/L BA and 2.0 ㎎/L NAA. Three types of regeneration in A, rusticana were clearly established, which could be applied to the study of morphogenesis and genetics at cell, tissue and organ levels.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.379-387
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• 2017

Various sizes (0.2 ~ 1.2 mm) and developmental stages (referred to as Stage 1 ~ 3) of apical and lateral meristems were excised, together or separately, directly from dormant buds of apple 'Hongro'. They were mixed infected by Apple scar skin viroid (ASSVd), Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV) and Apple stem grooving virus (ASGV), which are major viruses attacking apples. A total of 31 callus lines (> 10 mm in diameter) were obtained by culturing the explants on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 3.0 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-butyric acid (IBA), and they were subjected to RT-PCR analysis for virus detection. A high rate of virus elimination (expressed as the percentage of calli that did not amplify during RT-PCR, i.e., RT-PCR negative calli per total number of calli obtained) was achieved for ACLSV (100%), ASSVd (93.7%), and ASPV (93.7%), whereas it was only 25.8% for ASGV. ASPV was detected in the presence of 2 ~ 3 bracts. Simultaneous virus elimination of ASSVd, ASPV, ACLSV, and ASGV occurred during the meristem culture, in which the early stages of the dormant buds (Stage 1) were used, because ASGV was mostly eliminated during that stage. The results of the present study will be valuable for the production of virus-free apple trees.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.30-42
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• 1986

In order to find out the best media, explants and environmental conditions for induction of calluses and organogeneses of Pinellia ternata (Thunb.) Breit in vitro, various parts of adult have been cultured on Murashige & Skoog's medium containing various levels of 2,4-dichlorophenoxy acetic acid(2,4-D) and kinetin. The results obtained were as follows: Calluses were induced from the surface of apical meristem and leaf tissue. Formation and growth of calluses in petiole ex plants were best on the MS medium complemented with 2,4-D 2.0 mg/l and kinetin 0.2mg/l. But callus formation in stem ex plants of the nearest tuber was not induced at all kinds of media. Plantlets occured at all treatment except absence of growth regulator. Their numbers, size, leaf and fresh weight were promoted by 2,4-D 2.0mg/l and kinetin 0.2mg/l. Root growth was increased on the medium containing higher 2,4-D concentrations. Size and fresh weight of callus were increased at 25$^{\circ}C$ compared with 10, 20 and 30$^{\circ}C$, respectively. Optimal pH value was at 6.0 for growth of callus. Morphological aberrations were observed in plantlets, especially in regenerated leaves. The separation of the broad leaved plantlets and albino were observed in some cultures. Growth of plantlets after transplantation was best in pots with the sterilized vermiculte. But abnormal variants withered up.

• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.243-248
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• 2001

This study was peformed to find out the optimal conditions for the selection of transformed cells using already established transgenic plants. Several transgenic poplar (Populus alba$\times$P giandulosa) lines carrying npt II or hpt gene as a selectable marker were tested against kanamycin or hygromycin. Two culture explants, leaf discs and nodes, were compared regarding their sensitivity to the antibiotics. When leaf discs of untransformed control plants were cultured on callus inducing media in the presence of varying levels of kanamycin or hygromycin, only those cultured on the media containing lower than 50 mg/L kanamycin or 2 mg/L hygromycin formed callus. However, much higher concentration of kanamycin was needed to suppress the growth of axillary buds of untransformed plants. On the other hand, hygromycin at the concentration of 5 mg/L effectively suppressed shoot growth of untransformed plants. Root induction from untransformed plants could also be suppressed at the concentration of 50 mg/L kanamycin or 5 mg/L hygromycin. The transgenic plants showed resistance to 100 mg/L kanamycin or 50 mg/L hygromycin in the growth of callus, shoots, and roots. Hygromycin appeared to be more efficient in selecting untransformed cells than kanamycin.

• Korean Journal of Plant Tissue Culture
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• v.25 no.2
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• pp.135-139
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• 1998

Reciprocal interspecific hybrids between N. glauca(2n=24) and N. langsdorffii(2n=18) were obtained by intercrossing. One hundred percent of F$_1$ seeds was produced from intercrossing of N. glauca $\times$ N. langsdorffii, whereas the frequency of F$_1$ hybrid seed formation from N. langsdorffii $\times$ N. glauca was very low. However, all the hybrid seeds were germinated well and then grown to normal plantlets. All the plants of F$_1$ hybrids have chromosome number of interspecific hybrids (2n=21). From observation of morphological characteristic, the structure of petrol, leaf, flower, and the morphology of pollen have characteristics of F1 hybrid. Spontaneous tumors (genetic tumor) were formed from each F$_1$ hybrid; the genetic tumor arose at the reproductive phase when the maternal type of F$_1$ hybrid came from N. glauca, while the genetic tumor arose only after reproductive phase when the maternal type of F$_1$ hybrid came from N. langsdorffii. The genetic tumor actively proliferated on hormone-free medium and produced numerous teratoma shoots. In addition, normal leaf or stem explants of F$_1$ hybrid produced calli on hormone-free medium after 15 days of culture, the calli produced new numerous teratoma shoots after 30 days. The frequency of teratoma shoot formation from rnterspecific hybrid was higher in the N. glauca $\times$ N. langsdorffii than in the N. langsdorffii $\times$ N. glauca. Root development from the teratoma shoots was hardly obtained. Teratoma shoots without roots in vitro can form genetic tumor at the vegetative growth phase after tissue culture.

• Journal of Plant Biotechnology
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• v.29 no.3
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• pp.179-183
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• 2002

This study was carried out to investigate the influence of medium composition for in vitro mass propagation of Lycoris squamigera Max. After the disks of short stems, segments of leaf within bulb and scale were cultured on MS basal medium supplemented with various plant growth regulators, they were examined for the extent of callus formation, shoot and root regeneration. In the culture of stem disks, adventitious shoots were regenerated from the basal tissue of bulb scales, and combined medium of 1.0 mg/L 2,4-D or NAA＋2.0 mg/L BA or kinetin showed the the best response and 4∼6 shoots per explant formed. In the culture of leaf segments within bulbs, both MS medium supplemented with 1.0 mg/L NAA＋2.0 mg/L TDZ and with 1.0 mg/L 2,4-D＋1.0∼2.0 mg/L BA were produced callus profusely on the base of leaf tissue and 3∼6 shoots were regenerated per explant. In the scale segments culture, calli were produced on the basal tissue on medium with 1.0 mg/L 2,4-D＋1.0∼2.0 mg/L BA. The best result were shown on MS medium with 1.0 mg/L NAA＋2.0 mg/L TDZ, and 1.0 mg/L 2,4-D＋1.0∼2.0 mg/L BA. Maximum number of regenerated shoots was up to 10∼12. Adventitious root formation from explants were formed profusely on MS medium with 1.0 mg/L NAA＋2.0 mg/L kinetin. The most desirable method for mass propagation of plantlets was the shoot regeneration from scale segments then subsequently subcultured on medium for rooting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.110-114
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• 1981

These experiments were carried out to define the effects of NAA, 2, 4-D and Benzyladenine on the callus induction and the organ differentiation from the explants and to find out the vegetative propagation method of Korean ginseng. The results obtained are summarized as follows; 1. NAA was significantly effective in forming roots from the ginseng stem segment and the number of roots was increased by increasing NAA concentration in the medium. The roots were formed from both distal and proximal ends of the ginseng stem segments grown on the medium containing more than 2mg/L of NAA. 2. The amount of callus growth increased proportionatly with NAA concentration in the range of 4.0mg per liter in the medium. The callus was easly induced from stem segment than leaf segment and 2, 4-D was more effective in callus induction and growth than NAA. 3. The benzyladenine showed the significant inhibition effect in forming roots from ginseng explant. The callus was not induced with BA alone, but in BA and 2, 4-D or BA and NAA added medium, the callus was easily induced and its growth was also accelerated. The interaction effects between 2, 4-D and BA on the callus induction and growth were significantly higher than those between NAA and BA. 4. As the ginseng embryos were cultured on the M.S. medium supplemented with 2mg per liter NAA, number of shoots was significantly increased and the percentage of embryo which had shown more than 4 shoots later was 22.2%. On the medium containing 8mg per liter NAA, the ginseng embryo showed the normal growth of shoots and leaves, but increased roots and callus induction on the basal part of shoots. 5. When the shoots with 3 leaflets were cut in 1.5cm long and grown on the Blayde's medium containing NAA 1.0mg per liter, roots were formed at the proximal end of shoot, and a new ginseng seedling was successfully obtained.

• Journal of Plant Biotechnology
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• v.35 no.3
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• pp.229-234
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• 2008

An efficient micropropagation was established by using axillary bud explants from two-year-old tree(Echinosphorea koreensis Nakai), which has been known as a rare and endangered species. Among various basal media tested, DKW medium was shown to be the best for axillary shoot elongation. The addition of both BA and TDZ to the medium induced 6 to 10 shoots per explant during eight weeks of culture, without showing any abnormal morphology at the shoot proliferation stage. However, high concentration of TDZ(>0.05 mg/L) appeared to cause hyperhydration on either leaf or shoot at the later developmental stage. Approximately 20% of shoots produced roots by the addition of 1.0 mg/L NAA but not by IBA($0.2{\sim}1.0$ mg/L). Ex vitro micro-cuttings were better source for root induction; up to 58.6% of the micro-cuttings rooted when 100 mg/L IBA was applied to the soil(vermiculite). More than 90% of plantlets with roots were successfully acclimatized and grew normally in the field. Therefore, we suggest that this endangered tree species can be effectively micropropagated by axillary bud culture system developed in this study.

• Korean Journal of Plant Tissue Culture
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• v.24 no.1
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• pp.43-48
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• 1997

Apical meristems of Wasabia japonica were cultured on Murashige and Skoog's medium supplemented with cytokinins alone or together with 1.0 mg/L IAA. Shoot initials could be induced from leaf primordia on apical meristems. Calli and roots were formed on the medium containing cytokinins and 1.0 mg/L IAA in combination after 30 days of culture, but there were no callus proliferation. Shoot organogenesis began after 60 days of culture and these small shoots elongated when transferred to a medium containing 1.0 mg/L BA or kinetin. Shoots were formed directly without callus induction from apical meristems all the explants on the medium containing cytokinins variously, and most of the shoots proliferated multiple shoots which could be divided to obtain plantlets. Shoot multiplication rate in response to cytokinins was best on the medium containing 1.0 mg/L BA or 2.0 mg/L zeatin. Divided plantlets rooted well on MS medium containing 0.01 mg/L IBA after 15~30 days of subculture and the rooted plantlets developed into whole plants with multiple shoots. After rooting, the regenerated plants were washed and transferred to the pots containing sterilized soil.