• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.277-281
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• 2001

Embryogenic callus induction and plant regeneration methods were developed for native Kentucky bluegrass (Poa pratenes L.) ecotypes. Mature caryopses and immature inflorescences (20 mm in length) of 4 native ecotypes and 5 foreign cultivars were plated on MS medium (30 g/L sucrose, 3 g/L Phytagel) supplemented with 1 mg/L 2,4-D, and cultured in the dark at 24$^{\circ}C$. Most explants formed calli, but more embryogenic calli were induced from the explants of immature inflorescences than caryopses which produced mostly non-embryogenic rooty calli. In P77 ecotypes, immature inflorescence explants formed embryogenic calli with the rate of 62~95%, and those of field-grown plants were more efficient than greenhouse-grown ones in embryogenic callus induction. Plantlets were regenerated from the embryogenic calli when they were transferred to hormone-free MS medium, and grew to maturity without morphological variations in greenhouse.

• Journal of Plant Biotechnology
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• v.35 no.2
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• pp.133-140
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• 2008

The modification of DNA and histone plays an important role for gene expression in plant development. The objective of this research is to observe the effects of methylation on the gene expression during dedifferentiation from rice mature seeds to callus and differentiation from callus to shoots. The embryogenic callus with ability to shoot regeneration was not induced on the N6A medium supplemented with 5-azacytidine and abnormal callus with brown color was formed. When the normal rice callus was placed on the regeneration MSRA medium supplemented with 5-azacytidine, the shoot regeneration was inhibited. The results showed that 5-azacytidine, DNA demethylating agent, had negative effects on normal embryogenic callus formation and shoot regeneration. This suggested that DNA methylation of some genes was required for normal cell dedifferentiation and differentiation in tissue culture. The microarray and $GeneFishig^{TM}$ DEG screening were used to observe the gene transcript profile in callus induction and regeneration on N6A (N6 medium + 5-azaC) and MSRA (MS regeneration medium + 5-azaC). Subsets of genes were up-regulated or down-regulated in response to 5-azaC treatments. The genes related with epigenetic regulation, electron transport, nucleic acid metabolism and response to stress were up and down regulated. The different expression of some genes (germin like protein etc.) during callus induction and shoot regeneration was confirmed using RT-PCR and northern blot analysis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.366-370
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• 1993

This study was conducted to determine the optimum culture conditions for inducing callus and regenerating plantlets from cultured leaf tissues of Aralia elata. Young leaf tissues(1cm) of A. elata plant were cultured on MS medium supplemented with 2, 4-D and Thidiazuron. Embryogenic callus was induced along the leaf veins, more efficiently on the medium containing 1.0mg /1 Thidiazuron in 4 weeks after culture initiation. Calli were subcultured to proliferate on MS media containing 2, 4-D, Dicamba, Picloram, and Thidiazuron. Callus was better proliferated on the medium containing Dicamba than on the others.. However, callus subcultured on the medium containing Thidiazuron was more embryogenic and light green-colored, of which some showed embryoid-like structure on the surface. Hormone-free medium was more efficient to regenerate plantlets than media supplemented with Kinetin, BA, and Thidiazuron.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.236.2-236
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• 1995

• Proceedings of the Korean Society of Grassland Science Conference
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• 2001.06a
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• pp.93.2-94
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• 2001

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.232-236
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• 2004

In order to optimize tissue culture conditions for genetic transformation of orchardgrass (Dactylis glomerata L.), the effects of culture medium supplements on tissue culture responses were investigated with mature seeds of a cultivar, 'Roughrider', as explant tissues. The optimal concentration of 2,4-D for the induction of embryogenic callus from mature seeds was 3 mg/L. Plant regeneration frequency was 36.3% when embryogenic calli were cultured on the regeneration medium supplemented with 1mg/L 2,4-D and 3mg/L BA. Addition of 1 g/L casein hydrolysate and 300 mg/L L-proline improved frequencies of embryogenic callus induction and plant regeneration up to 57.3 and 60.7%, respectively. Supplementation of the media with 10 mga $\textrm{AgNO}_3$ and 40 mg/L cysteine enhanced frequencies of callus induction and plant regeneration. Efficient regeneration system established in this study will be useful for molecular breeding of orchardgrass through genetic transformation.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.49-55
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• 2017

We investigated the callus induction and plant regeneration ability of 16 maize genotypes, including the Korean inbred lines, using 9 to 15 day-old immature zygotic embryos from maize grown in pots and from field cultures. Immature zygotic embryos placed on MS medium supplemented with L-proline 0.7 g/L, MES 0.5 g/L, Dicamba 1.5 mg/L, 2,4-D 0.5 mg/L, $AgNO_3$ 4 mg/L, and sucrose 20 g/L, showed the highest frequency of callus induction. The highest number of shoots regenerated when the embryogenic callus were transferred to MS medium supplemented with 5 mg/L zeatin. The root formation was observed when shoots were grown on MS medium supplemented with 0.2 mg/L indole-3-butyric acid (IBA). Additionally, under the same culture conditions, immature zygotic embryos from maize grown in the field also had a high frequency of plant regeneration. Except one genotype, 15 genotypes showed callus induction and shoot regeneration. Among the 16 genotypes tested, H99, B98, HW3, and B73 yielded the best plant regeneration. H99 showed maximum shoot formation from the primary embryogenic callus. The results suggest that genotypes and growth conditions of the maize plant plays very important roles for enhancing the embryogenesis competence of immature zygotic embryos. The successful regeneration from immature zygotic embryos of maize inbred lines provides a basis for molecular breeding of new cultivars by genetic transformation.

• Journal of Plant Biotechnology
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• v.35 no.1
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• pp.81-86
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• 2008

This study describes conditions for plant regeneration from protoplasts-derived from embryogenic callus of satsuma mandarin. Plants were generated via somatic embryogenesis. Protoplasts isolated directly from nucellar callus induced from immature ovule of satsuma mandarin cv. Okitsu (Citrus unshiu Marc.) were cultured in 0.6M $BH_3$ medium. Cell division and plating efficiency were affected by protoplast culture method. The liquid over solid method was the most effective for formation of microcalli. Most of microcalli grew rapidly and transferred onto embryoid formation medium. Optimum embryoid formation medium was MT medium containing 1.5 g/L malt extract, 0.146 M sucrose and the medium for plantlet regeneration was MS medium containing 0.09M sucrose, 1.0 mg/L $GA_3$. No differences were noticed in growth habits and leaf characters such as shape, thickness, and colour between protoplast-derived plants and nucellar seedlings. This plant regeneration system from protoplasts-derived from embryogenic callus provides an alternative way for producing new scion and rootstock cultivar from citrus species which can not be crossed.

• Korean Journal of Medicinal Crop Science
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• v.2 no.1
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• pp.38-43
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• 1994

The effect of thidiazuron on callus growth and shoot regeneration of Solanumspecies was very positive. Increasing concentrations of thidiazuron stimulated callus growth of Solanum ptycanthum and Solanum nigrum. Shoot regeneration of S. ptycanthum and S. nigrum was greater on medium with thidiazuron than that with IAA and BA. Thidiazuron at $0.5{\mu}M$ or above increased the number of shoots regenerated from S. ptycanthum calli compared to the IAA with BA. High concentrations of thidiazuron $( >I{\mu}M)$ increased the number of shoots than BA or low levels of thidiazuron and IAA or BA The addition of IAA to thidiazuron media reduced S. ptycanthum shoot formation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.4
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• pp.303-308
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• 1999

The conditions for callus formation and plant regeneration were confirmed in birdsfoot trefoil (Lotus corniculatus L.). Among SH (Schenk and Hildebrandt), MS (Murashige and Skoog) and N6 medium (Chu), SH medium was highest degree of efficiencies respectively in callus formation and plant regeneration. In this study, we determined volume of hormones and other compounds appended in media. For callus formation, only $3mg/{\ell}$ of 2,4-D (2,4-dichlorophenoxy acetic acid) was appended in their media. For plant regeneration, we used BOi2Y medium (Bingham et al.). We obtained birdsfoot trefoil plants from callus by regeneration, about sixty days later transfer calli to regeneration media.