• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.213-218
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• 1993

An experiment was carried out to investigate the effects of plant growth regulators on the growth and fiber yield of ramie. Gibberellin (GA) and Atonic acid were applied at the various levels of application dates, application frequencies and concentration. Stem growth of ramie increased greatly by applying GA on the meristem of shoot apex. Among three treatments of application frequencies of GA, that is, one time application at the stage of stem length with 50cm, twice applications at the stem length of 50cm and 100cm, and three times applications at stem length of 50cm, 100cm and 150cm, stem growth increased more as application frequency increased. GA application is more effective on stem growth at the later stage of growth than the earlier growth stage. GA treatment of 100 to 300 ppm is more effective on stem elongation than 50 ppm, which was due on the elongation of internodes without increase in number of nodes. One time application of GA enhanced leaf growth more or less regardless of concentration, but GA was applied more frequently, leaf growth was inhibited more at higher concentration. Fiber yield was the highest at the treatment of three times application of GA with 100 ppm. This treatment also showed the highest percentage of fiber with 5.3%, which is much higher value compared with that of control treatment with 4.6%. Atonic acid was less effective on stem elongation than GA, but it also seemed to be effective on the enhancement of fiber development.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.314-324
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• 1998

This study was carried out to investigate the herbicidal action characteristics of EK3143 and EK3150, newly synthesized cyclohexanedione analogues, and their inhibitory effects on the acetyl-CoA carboxylase activity isolated from various plants. Sethoxydim, a typical cyclohexanedione herbicide, had a high herbicidal activity against only grasses with growth inhibition, leaf chlorosis and necrosis. EK3143 and EK3150 had a lower effect against grasses but a higher effect against broadleaf plants such as black nightshade and velvetleaf than sethoxydim had. Low rate application of EK3143 induced leaf bleaching(whitening), while high rate application induced the same symptoms as those of sethoxydim. EK3150 induced more significant whitening, additionally accompanying a curling of meristem part in broadleaf plants. A consistant tendency was observed between the growth inhibition against grasses and the senstivity of grass ACCase to these compounds, but not between herbicidal activities against broadleaf plants and the senstivity of dicotyledonous ACCase; i.e. EK3150, which had higher herbicidal activity against black nightshade and velvetleaf than EK3143 had in greenhouse, rather showed lower ACCase inhibition. In EK3150-treated barnyardgrass, growth inhibition occurred prior to decrease of photosynthetic pigments, in contrast to that of norflurazon and EK3140. These results suggest that EK3143 and EK3150 may have two target sites, ACCase and an unknown site on fatty acid synthesis related to growth inhibition and bleaching respectively, and their symptoms would be appeared in different degree by a differential binding affinity between two action sites.

• Korean Journal of Weed Science
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• v.16 no.2
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• pp.160-170
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• 1996

Several physiological responses were investigated in plants treated with TOPE as a preliminary step to know its action site. Unlike photo-dependent diphenylethers, herbicidal activity of TOPE appeared slowly and its typical symptoms were both burning of leaf blades and abnormal division of meristem in grasses, Similarly, both leakage of cell electrolytes and the curling of cotyledon margin were also shown in cucumber(Cucumis sativus L.). Biosynthesis of chlorophyll in etiolated cucumber cotyledon was not inhibited directly by treatment of TOPE at low light intensity(5.5${\mu}$ mol $m^{-2}s^{-1}$ PAR) and protoporphyrin IX was not also accumulated. The contents of phytoene, phytofluene and ${\beta}$-carotene were abnormaly increased. Photosynthesis was inhibited only at high concentration. Mitochondrial respiration was inhibited at high concentration but rather increased significantly at 10${\mu}$M of TOPE. However, respiration inhibitors did not alleviate the two symptoms of TOPE in cucumber cotyledon. In the same experiments, using inhibitors of protein or nucleic acid biosynthesis, only one of the two symptoms was alleviated by chloramphenicol and cycloheximide. In contrast, both symptoms were alleviated by actinomycin-D and hydroxyurea, suggesting that nucleic acid metabolism might be preferentially related to the mode of action of TOPE. DNA, RNA and protein contents were accumulated in both cucumber cotyledon and rice (Oryza sativa L.) routs treated with TOPE, and the DNA of them was increased at first. Thus, it is conjectured that TOPE increase nucleic acid metabolism directly or indirectly, and then disturb various metabolic pathways causing abnormal physiological and morphological effects followed by final death.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.1-6
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• 2007

Effect of BA concentrations and culture methods on in vitro plant multiplication from shoot-tip cultures of Wasabia japonica was studied. Shoot-tips with leaf primordia and apical meristem were cultured on MS basal medium for all the experiments. Liquid medium for 2 weeks followed by semi-solid medium for 4 weeks containing 1.0 mg/L BA was the best to number of shoots (22.8) and shoot length (3.5 cm). Shoots proliferated could be divided into ca. 5 to 11 of cultures for the multiplication of plantlets. Divided plantlets showed root formation (90%) well onto MS basal medium without growth regulators like IBA and NAA. After rooting, all the plantlets transferred into the pots containing composed soil (bio-media Co., peatmoss $8{\sim}10%$, coir dust $66{\sim}70%$, zeolite $13{\sim}17%$, vermiculite $3{\sim}7%$, perlite $2{\sim}4%$) and grown well into whole plants with multiple shoots.

• Journal of Life Science
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• v.20 no.9
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• pp.1314-1323
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• 2010

In this study, we constructed various kinds of binary vectors with the pPZP backbone for co-overexpression, tissue- or development-specific expression and stress-inducible expression, and validated them for ectopic expression of target genes. Using a modified CaMV 35S promoter, a binary vector was generated for co-overexpression of two different genes and was confirmed to be efficient for overexpressing two different target genes at the same time and place. Binary vectors containing At2S3, KNAT1 or LFY promoters were constructed for tissue-specific or development-specific gene expression, and the binary vectors were suited for embryo/young seedling stage-, shoot apical meristem- or leaf primordia-specific expressions. Furthermore, the binary vectors containing RD29A or AtNCED3 promoters were validated as suitable vectors for gene expression induced by abiotic stresses such as high salt, ABA, MV and low temperature. Taken together, the binary vectors constructed in this study would be very useful for analyzing the biological functions of target genes and molecular mechanisms through ectopic expression.

• Korean Journal of Plant Resources
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• v.31 no.5
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• pp.515-521
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• 2018

This was carried out to develop a chromosome-doubled (12x) persimmon that will be used as a crossing parent to select seedless persimmon cultivars with the change of the consumption trend recently. To obtain a chromosome-doubled (12x) persimmon, colchicine was applied at the meristem of seedlings in vitro derived from cross among hexaploid persimmon (Diopyros kaki Thunb.). These were treated with 0.03%, 0.05% and 0.1% colchicine respectively for doubling chromosome, and it was most effective at the concentration of 0.05% colchicine. After colchicine treatment, we conducted tests to elucidate conditions for inducing shoot and root development. As the result, the shoots grew best when cultivated at 1/2MS media plus 10 and $30{\mu}M$ zeatin respectively, and the roots grew best when cultivated at 1/2MS media after dipping for 5 seconds at 10 mM NAA+5% DMSO. We also compared seedlings that have chromosome (6x) do not doubled and crossing parents (6x) and chromosome-doubled seedlings (12x). As the result, these chromosome-doubled seedlings (12x) showed lower stomatal density and larger stomatal size.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.65-72
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• 1990

The mitotic cycle duration and component plase periods of rice (Oryza sativa L. 'Sumjinbyeo and Seokwangbyeo') root merisem cells at 15, 20, and 30$^{\circ}C$ were determined the use of tritiated thymidine, In this work, the time interval between the maxima of sequential mitotic appearances of marked cells was used to estimate the mitotic cycle duration (MCD) of rice, The MCD of rice of the cultivar 'Sumjinbyeo' and 'Seokwangbyeo' at 20. and 30$^{\circ}C$ was 12. and 20hr, respectively. But the MCD of 'Sumjinbyeo' and 'Seokwangbyeo' was 18 and 20hr, at 15$^{\circ}C$. respectively. The MCD decreased with increasing temperature, The duration of component phase of rice cultivar 'Seokwangbyeo' were essentially the same ratio at 20$^{\circ}C$ and 30$^{\circ}C$. but in 'Sumjinbyeo' cultivar the ratio of $G_1$ period was almost doubled while those of $G_2$ and M were decreased by almost two times at 20$^{\circ}C$ and 30$^{\circ}C$. Deoxyribonucleic acid (DNA). Ribonucleic acid (RNA), and protein synthesis were reduced with increasing temperature from 15$^{\circ}C$ to 30$^{\circ}C$ while the MCD was decreased, This result suggest that DNA, RNA and protein synthesis may not affect the MCD from 15$^{\circ}C$ to 30$^{\circ}C$ in rice.

• Korean Journal of Plant Tissue Culture
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• v.21 no.3
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• pp.161-166
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• 1994

Since garlics (Allium sativum L.) are propagated through cloves, infection by virus or other pathogens may become severe problem if not using high quality seed bulbs every year resulting in the reduction of yield and bulb quality, In order to solve this problem, the establishment of virus-free bulb production and its supply system have been required because no chemicals were found to eliminate viruses from seed bulbs. This experiment was conducted to develop an effective production technique of high quality seed bulbs using shoot-tip culture. Over 90% of shoot-tips explanted on January L 1990 were survived at constant temperature of either 20, 24 or 28$^{\circ}C$, wheres 88% at alternate temperature (28/20$^{\circ}C$). The growth of shoot and root was most vigorous at constant 24$^{\circ}C$, and least at alternate temperature (28/20$^{\circ}C$) condition. When shoot-tips were explanted June 21 to August 1,1991, survival and growth of shoot-tips was most vigorous on MS medium supplymented with 0.1 mg/L NAA and 2 mg/L kinetin and least 1 mg/L Gh$_3$. The shoot-tips taken from the seed bulbs stored at 4$^{\circ}C$ for 15 to 60 days were placed on MS medium, shoot growth and in vitro bulblet formation increased slightly as affected by the increase of told treatment period at 4$^{\circ}C$.

• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.73-80
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• 2003

Useful Dianthus species were collected and selected from two native and seven foreign species distributed in Gangwon province. For in vitro breeding,. callus was induced from the explants of apical meristem, leaf, stem and the in vitro adventitious shoots on MS basal medium with 2.0 mg/L 2,4-D and 0.5 mg/L BA at 27$^{\circ}C$ under continuous light. After 3 weeks of culture, calli initiated the most highly from the leaf explants of D. chinensis Organogenic calli were able to be selected from the adventitious shoot-derived calli. For shoot regeneration, these organogenic calli were cultured on MS medium with the combination of 0.1 mg/L NAA＋1.0 mg/L BA under continuous light. Multiple shoots were proliferated with low frequency (about 30%) from those adventitious shootderived calli. Also, shoots initiated directly from the adventitious shoot explants without callus formation at high frequency of 52% when cultured on N6 medium containing 0.1 mg/L NAA and 1.0 mg/L BA in D. gratianopol. Multiple shoots and plantlets grew well and rooted on MS medium supplemented with 0.1 mg/L NAA. Regenerants with well-developed roots were transferred to 8-cm pots containing vermiculite at 85% relative humidity and 27$^{\circ}C$ These plantlets were acclimatized in artificial soil mixture and transferred to the greenhouse for flowering with normal phenotypes. M28 Mutant line was selected with white flowers from 0.03M EMS-treated organogenic calli derived from in vitro adventitious shoot explants of D. chinensis and set seeds.