• Korean Journal of Plant Tissue Culture
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• v.21 no.1
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• pp.7-14
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• 1994

Immature zygotic embryos of five Korean soybean cultivars cultured on Murashige and Skoog's (MS) medium supplemented with various concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) produced somatic embryos without forming an intervening callus. The highest frequency (up to 90%) of somatic embryo formation was obtained when zygotic embryos were cultlued on medium containing 1 to 2 mga 2, 0-D in four cultivars. However the frequency was highly variable to the cultivars. Transversely sliced primary somatic embryo halves were also capable of forming secondary embryos at frequencies of up to 70% when cultured on medium containing 0.1 to 1 mg/L 2,4-D. Somatic embryos formed on zygotic embryos cultured on medium containing 0.1 to 0.2 mg/L 2,4-D had two cotyledons more frequently than one horn-type cotyledon and those on medium containing 0.5 to 4mg/L 2,4-LD had a horm-type cotyledon at a prominently higher freequency. However somatic embryos on medium containing 10mg/L or higher concentrations of 2,4-D were usually shunted at the globular stage even after transfer to medium containing lower concentrations of 2,4-D or other growth regulators. non somatic embryos with one or two cotyledons or a hem-type cotyledon were transferred to medium containing $GA_3$, those with two cotyledons converted to plantlets at a higher frequency (25%) than the others.

• Korean Journal of Plant Tissue Culture
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• v.27 no.6
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• pp.453-459
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• 2000

Three rice (Oryza sativa L. var Dong-Jin) mutants (DTR1, DTR2, DTR3) resistant to S-methyltryptophan (5MT) were selected by mutagenized M3 seeds. The frequency of chlorophyll mutations induced by the EMS (0.2%) treatment performed 2 hours after flowering is clearly higher than that induced by other treatments in M1 generation. Progeny obtained from the self-pollinating of 5MT-resistant lines segregated with 3 : 1 of resistant to sensitive ratio. Furthermore, the ratio of homozygote to heterozygote in 5MT-resistant plants of the M4 generation was 1：2. These results show that 5MT resistance was inherited as a single dominant nuclear gene. The resistance was also expressed in callus derived from seeds. Total free amino acid content in homozygous seeds of DTR1 and DTR2 showed about 1.7 fold-increased compared to the wild-type seeds. In particular, the levels of phenylalanine and Iysine were, respectively, 6.2 and 3.2 times higher than those in the wild-type seeds. However, seeds of DTR3 had lower levels of free amino acid than the wild-type seeds. This result indicate that these mutants as a significant step towards the production of new rice with balanced amino acid content.

• Journal of Plant Biotechnology
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• v.41 no.3
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• pp.134-139
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• 2014

The aim of this study was to establish the condition of regeneration for white balloon flower (Platycodon grandiflorum DC. cv. Jangback) and to manage for the raising of seedling with in vitro regenerated plants. It was examined that 0.5 mg/L of NAA and 1.0 mg/L of BA was the best composition for the callus and shoot induction (up to 600%). NAA was better than IBA for the induction of root and it took 16.9 days for the induction of rooting on the MS soild media containing 0.5 mg/L of NAA and the final rooting ratio was up to 75%. Out of 5 different bed soils purchased from local market, "Tosil" was identified to be the best for the acclimation and growth of in vitro regenerated balloon flower. In detail, on 8 weeks after planting of in vitro regenerated plants in pots containing "Tosil" bed soils, the plant hight was increased up to 2-fold (12.8 cm), 3.5-fold (27) for the number of leaf and 1.5-fold (4.5 cm) for the leaf length when compared to the other four bed soils, respectively. Our preliminary results indicate that it is possible to prevent the occurrence of blue balloon flower in the massive cultivated area of white balloon flower by providing the seedlings raised from in vitro regenerated plants.

• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.175-179
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• 2005

To develop a high efficiency plant regeneration system from in vitro cultures of strawberry, cv. Yeobong, petiole and leaf explants were cultured on MS basal medium containing a combination of 0.5 mg/L IBA and 3.2 mg/L kinetin or zeatin or benzyl amino purine (BAP) for 6 weeks, and leaf explants with dark pretreatment for a week ($T_1$), 2 weeks ($T_2$), and 4 weeks ($T_3$) were cultured on medium supplemented with 0.5 mg/L IBA and 3.2 mg/L zeatin under 16 hr photoperiod for 6 weeks. Shoot organogenesis was observed from the greenish calli containing minimal anthocyanin formed at proximal cutting edges of the leaf explant (57%) when cultured adaxial side on the medium, whereas was directly formed from a cutting edges of petiole explant (6.3%). Frequency of callus formation and shoot organogenesis at large size of leaf explant ($1.0{\sim}1.5\;cm^2$) was higher than small size ($0.5{\sim}1.0\;cm^2$), and dark pretreatment significantly improved the frequency of leaf explants that produced calli and shoots. The maximum frequency (87%) for shoot organogenesis was obtained from the leaf explants that transferred to a 16 hr photoperiod condition after the initial 4 weeks dark period. The improved frequency (87%) in comparision with control without dark pretreatment (27%). When the shoots were transferred to 1/2 MS basal medium, formed roots with 20 d of culture. The rooted plants were subsequently transferred to the pots and to the field.

• Korean Journal of Plant Tissue Culture
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• v.25 no.5
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• pp.289-293
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• 1998

We investigated the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in methanol extracts of 64 cultured cell lines, which were derived from various plant species, and the ascorbate content in cell lines, which showed a high radical scavenging activity. Thirteen cell lines revealed the antioxidative activity ($IC_{50}$) by methanol extracts of less than 50 mg in cell fresh wt. Of them, six cell lines showed the same Rf value as ascorbate on the DPPH sprayed silica gel TLC. The ascorbate content in cell lines of Rosa multiflora, Scutellaria baicalensis, and Achyranthes japonica showed 48.5, 30.3, and $16.8\;\mu\textrm{g}$ per g cell fresh wt by HPLC analysis, respectively. In callus cultures of S. baicalensis, the concentration of ascorbate reached a maximun ($39{\pm}3.4\;\mu\textrm{g}/g$ cell fresh wt) on 30 days after subculture, which corresponded to the stationary growth phase, and subsequently decreased by successive culturing.

• Korean Journal of Plant Tissue Culture
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• v.26 no.3
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• pp.163-169
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• 1999

This study was conducted to produce herbicide resistant plants by transferring phosphinothricin acetyltransferase (PAT) gene into Populus alba $\times$ Populus glandulosa No .3 using Agrobacterium tumefaciens MP 90/PAT. Leaf segments from in vitro grown shoots of hybrid poplar No. 3 were soaked in a AB medium containing Agrobacterium tumefaciens MP 90/PAT for 10 min and cocultivated for 2 days on MS medium containing 1.0 mg/L 2,4-D and 0.2mg/L kinetin (CIM). Putative transformed calli could be selected after cocultivation of leaf segments on CIM supplemented with 50mg/L kanamycin and 500mg/L cefotaxime for 3 weeks. The selected calli were cultured on CIM supplemented with 50 mg/L kanamycin and 500 mg/L cefotaxime for 5~8 weeks before transfer to WPM containing 1.0mg/L zeatin, 0.1mg/L BAP, 50 mg/L kanamycin and 500mg/L cefotaxime for shoot regeneration. Shoots were regenerated from the callus after 4 week cultivation, and the regenerants were grown on the same medium for 7~l0 weeks. The plants rooted on 1/2 WPM containing 0.2 mg/L IBA and 50 mg/L kanamycin. To confirm the gene insertion into plants, GUS activity was detected by histochemical assay in the transformed plants. Finally, the presence of both NPT II and PAT genes from the transgenic plants were confirmed by PCR amplification with the gene specific primers and subsequent PCR-Southern blot with DIG-labeled PAT gene probe. After acclimatization in pots for 4 weeks, the plants were sprayed by 3 mL/L of Basta to test resistance to the herbicide. The transgenic plants remained green, whereas all the control plants died after one week.

• Korean Journal of Plant Tissue Culture
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• v.26 no.3
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• pp.197-203
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• 1999

The albino plants of tobacco (Nicotiana tobacum L. cv. BY-4) were isolated from seed populations that were induced by heavy-ion ($^{14}N$) beam irradiation to proembryo and the in vitro growth and differentiation have been characterized. The in vitro cultured albino plants showed significant reduction of chlorophyll content and possessed larger number of stomata on both upper and lower epidermis than that of wild-type plants. Stem growth of the mutants remained dwarfed, however, the internode recovered its normal length after GA$_3$ treatment (10.0mg/L) on the MS medium containing sucrose under continuous light. When explants of leaf blades of albino plants were cultured, multiple shoots formed directly on MS medium containing 1.0mg/L of BAP or kinetin and a large number of calli were induced on the MS medium containing 1.0mg/L NAA or 1.0 mg/L 2,4-D. The albino calli regenerated multiple albino plantlets in the MS medium containing 0.1mg/L NAA + 1.0 mg/L BAP. No significant differences between the wild-type and albino plants were detected in the multiple shoot induction, callus formation from the explants and the plantlets regeneration from calli. In addition, albino plants have a similar organogenesis Pattern to that of the wild-type in the media with different combinations of NAA (0 to 5.0mg/L) and BAP (0 to 5.0mg/L) treatment. These results indicate that the albino mutant has the same normal regeneration ability as that of wild-type, although the mutant has lost functions in photosynthesis, such as pigmentation.

• Korean Journal of Medicinal Crop Science
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• v.10 no.1
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• pp.41-45
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• 2002

An efficient and reproducible procedure for the large scale propagation of Hovenia dulcis Thunb. is described. Shoot primodia emerging from the leaf surface was induced from MS medium supplemented with NAA. Stem cuttings were suitable explants for multiple shoot proliferation. They produced axillary shoots which branched repeatedly, yielding an average of 7 shoots per explants after 4 weeks in culture, when cultured on a woody plant medium (WPM) containing 0.1mg/l BA and 0.1mg/l NAA. Stem, leaf and root segments from axenic seedlings were used as explant source to induce somatic embryogenesis. A high frequency of somatic embryos were induced directly from leaf in MS medium with NAA, 2,4-D and in medium containing NAA, 2,4-D with BA. Somatic embryos were germinated in MS medium supplemented with 1mg/ l $GA_3$. Somatic embryos proliferated secondary somatic embryos rapidly after transfer to MS medium supplemented with 1mg/ l kinetin, 1mg/ l $GA_3$ and 2% dextrose.

• Korean Journal of Plant Tissue Culture
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• v.25 no.2
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• pp.109-113
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• 1998

In this study we tried to transform an antimicrobial peptide gene (Shiva) under the promoter of tomato phenylalanine ammonia-lyase (tPAL5) into tobacco and potato plants. Antimicrobial peptide gene was isolated originally from giant silk moth (Hyalophora cecropia) and modified ie nucleotide sequence to increase antimicrobial activity. Transgenic tobacco plants were regenerated and their seeds were tested on the media containing kanamycin (500 mg/L). The results of PCR amplification and genomic Southern blot hybridization confirmed the integration of construct (tPAL5 promoter-Shiva-NOS-GUS-NOS) into chromosome. We observed that one of the transgenic tobacco plants showed chromosome rearrangement when integrated. In case of potato transformation, the efficiency of regeneration was maximized at the medium containing Zeatin 2mg/L, NAA 0.01mg/L, GA$_3$ 0.1mg/L. We also observed the high expression of GUS (${\beta}$-glucuronidase) enzyme which was located next to the terminator sequence of nopaline synthase gene (NOS) in the vascular tissue of stem, leaves of transgenic potatoes. This result suggested that a short sequence of Shiva gene (120 bp) and NOS terminator sequence might be served as a leader sequence of transcript when translated.

• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.283-288
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• 1998

The bialaphos is a potent inhibitor of glutamine synthease in higher plants and is used as a non-selective herbicide. We have used the bialaphos resistant gene(Bar) encoding for an acetyltransferase isolated from Streptomyces hygroscopicus SF1293. Callus derived from mature seeds of rice(Oryza sativa L. cv. Dong Jin) were co-cultivated with Agrobacterium tumefaciens EHA101 carring a plasmid pGPTV-HB containing genes for hygromycin resistance (HygR) and Bar. Transgenic plants showing in vitro resistance to 50 mg/L hygromycin and 10 mg/L bialaphos were obtained by using a two-step selection/regeneration procedure. Transformation efficiency of rice was about 30% which was as high as reported in other dicotyledons. Progenies ($\textrm{T}_{1}$ generation) derived from primary transformant of 17 lines were segregated with a 3 resistant : 1 sensitive ratio in medium containing hygromycin and bialaphos. Stable integration of Bar gene into chromosomal DNA was proven by Southern blot analysis of genomic DNA isolated from $\textrm{T}_{2}$ progenies. Transgenic plants ($\textrm{T}_{3}$) grown in the field were resistant to bialaphos (Basta) at a dosage lethal to wild type plants.