• Korean Journal of Medicinal Crop Science
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• v.24 no.3
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• pp.177-182
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• 2016

Background: Many Taraxacum spp. plants are widely used in medicine, but some of them have propagation problems, such as strong dormancy and poor germination rates. This study investigated the effects of temperature, gibberellic acid ($GA_3$), and potassium nitrate ($KNO_3$) on seed germination in Taraxacum ohwianum. Methods and Results: The seeds (NIBRGR0000135524) were exalbuminous, and their length and width were $4.54{\pm}0.032mm$ and $0.97{\pm}0.029mm$, respectively. Various germination temperatures were tested (15, 20, 25, and $30^{\circ}C$), the optimum temperature for germination was found to be $20^{\circ}C$ (31.3%). High temperature ($30^{\circ}C$) resulted in non-typical seedlings (thickened and crumpled cotyledons, with a restricted root system). To increase the germination capacity, $GA_3$ (200, 500, and $1,000mg/{\ell}$) or $KNO_3$ (20, 50, 100, 200, and $500mg/{\ell}$) solutions were used as pre-soaking solutions instead of water. The $GA_3$ treatments increased the germination percentage and rate, but germination percentage was higher with the $KNO_3$ treatments. Under the $50-200mg/{\ell}\;KNO_3$ treatments, the germination percentage exceeded 80% after 12 days, and $50mg/{\ell}\;KNO_3$ was notably effective (91.2% after 15 days). Conclusions: T. ohwianum seeds showed improved germination at low temperatures. The best method for germination was presoaking in $50mg/{\ell}\;KNO_3$ for 24 h, in the dark at $4^{\circ}C$, and then incubating the germinated seed at $20^{\circ}C$ for 15 days.

• Journal of Plant Biology
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• v.32 no.4
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• pp.255-264
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• 1989

Ginseng zygotic embryos, seedlings, and exised cotyledonary nodes were cultured on Murashinge and Skoog's(MS) medium, supplemented with 6-benzyladenine(BA) and gibberellic acid(GA3) to induce flower buds. As the concenteration of nitrogen compounds in MS medium was reduced to half of its strength, the flowering frequency of zygotic embryos increased up to 90%. The optimum concentration of sucrose in the medium for flowering of seedlings was 30-60 g/1. In all cases flower buds were formed on elongated axillary branches from the cotyledonary nodes, while the apices remained vegetative. When zygotic embryos and excised cotyledonary nodes were cultured on the medium, supplemented with all possible combinations of BA, GA3, and abscisic acid(ABA) of 5 $\mu$M indole-3-acetic acid(IAA) in the above combinations did not affect flowering. These results suggest that cytokinins, gibberellins, and inhibitors play primary, permissive, and preventive roles, respectively, in the induction of flowering of ginseng.

• Journal of agriculture & life science
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• v.46 no.6
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• pp.9-15
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• 2012

This study was conducted to increase grape quality by treating plant growth regulator (PGR) in 'Campbell Early' grape. Foliar application of gibberellic acid ($GA_3$) at $5mg{\cdot}L^{-1}$ on flower cluster of 'Campbell Early' grape at 3-5 unfolded leaf stage effectively increased columella length, berry weight, soluble solid contents and promoted skin color development. Foliar application of $20mg{\cdot}L^{-1}$ abscisic acid (ABA) mixed with $5mg{\cdot}L^{-1}$ of $GA_3$ on flower cluster of 'Campbell Early' grape at 3-4 unfolded leaf stage effectively increased skin anthocyanin contents without any detrimental effects on berry enlargement and columella growth. Foliar application of $2.5mg{\cdot}L^{-1}$ thidiazuron mixed with $5mg{\cdot}L^{-1}$ of $GA_3$ on flower cluster of 'Campbell Early' grape at 3-4 unfolded leaf stage effectively increased fruit quality indices such as higher soluble solid contents and less titratable acidity.

• Applied Biological Chemistry
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• v.20 no.2
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• pp.242-246
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• 1977

In the barly coleptile sections treated with either $1{\times}10^{-5}M$ abscisic acid (ABA) or $1{\times}10^{-5}M$ gibberellic acid (GA), the time course changes of ribonuclease (RNase) activity and ribonucleic acid (RNA) profiles were studied. The results may be summarized as follows: 1. While GA suppressed RNase activity, ABA activated it. 2. High level of s-RNA and low level of r-RNA compared with normal plant sections in hormone-untreated coleoptiles seemed to be the results of increased RNase activity in the incubation period. 3. While GA retarded the decomposition of r-RNA, ABA activated it and the results seemed to be related with RNase activity. 4. GA activated the synthesis of RNA-DNA component, and ABA suppressed it. 5. Increase in the amount of s-RNA with the treatment of ABA may be due to the decomposition of r-RNA.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.522-527
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• 2010

Gibberellic acid ($CA_3$) is used in many industries and constitutes the primary gibberellins produced by fungi and bacteria. However, there is no information on $CA_3$ production by Methylobacterium oryzae CBMB20, a novel plant growth promoting bacterium. We investigated the favorable carbon (C) and nitrogen (N) sources and ratios and cultural conditions, such as incubation temperature, pH of the culture medium, and incubation period for the maximum production of $CA_3$ by Methylobacterium oryzae CBMB20. Maximum $CA_3$ production was observed in ammonium mineral salt (AMS) broth supplemented with Na-succinate and $NH_4Cl$ as C and N sources, respectively. The maximum $CA_3$ production was found at the C/N ratio of 5:0.4 g $L^{-1}$. The highest $CA_3$ production was obtained when the bacterial culture was incubated at $30^{\circ}C$ for 96 h at pH 7.

• Journal of Ginseng Research
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• v.26 no.1
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• pp.17-23
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• 2002

Gibberellic acid (GA) was applied to field-grown 3-year-old North American ginseng (Panax quinqueiolius L.) between 1 and 4 times, before and during bloom in 1999. Applications of both GA$_3$ and GA$\sub$4+7/ four times (x4) to the developing inflorescences increased maximum pedicel length, and seed head diameter and height. Treatment with GA$\sub$4+7/ increased mean and total root fresh weight linearly, whereas those treated with GA$_3$ did not show similar increases. Both GA$_3$ and GA$\sub$4+7/ at 50, 100 and 200 mg L$\^$-1/ (x4) increased the incidence of breaking of dormancy of perennating buds with GA$_3$ being twice as effective as GA$\sub$4+7/. Both GA$_3$ and GA$\sub$4+7/ treatments resulted in an increased number of new bud initials forming per root, with the number of new initials per root increased two-fold by the GA$_3$ sprays compared to GA$\sub$4+7/.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.296-302
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• 2014

The foliage of variegated Solomon's seal is excellent in cut flower arrangements. However, it has a restricted marketing period because the harvesting is limited in spring and summer. The increased interest requires the year-round production, thus techniques for dormancy breaking and forcing without low temperature treatment is needed. Therefore, experiments were conducted to d etermine whether gibberellic acid (GA) could break dormancy in variegated Solomon's seal. Thes prouting of dormant bud did not occur throughout the experiment when $GA_3$ $400mg{\cdot}L^{-1}$ was applied to dormant rhizomes as a soil drench. However, when plants were treated with a GA drench after scratch with razor blade or were given direct injection of GA, percent sprouting was increased up to 100 or 83.3%, respectively. However, because treatments with razor or syringe may damage internal organs, we tested another method, scarifying the rhizomes with sodium hypochlorite (NaOCl). Rhizome scarification with 4% NaOCl for 6 or 24 hours followed by drench of $GA_3$ $400mg{\cdot}L^{-1}$ increased the dormancy breaking percentage to 70 or 86.7%, respectively. Moreover, scarified and GA-treated rhizomes produced more leaves than untreated or GA-soil drenched plants in the glasshouse. These results showed the possibility of year-round production of variegated Solomon's seal foliage with rhizome scarification and GA treatments.

• Korean Journal of Medicinal Crop Science
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• v.24 no.4
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• pp.284-293
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• 2016

Background: Developing new ginseng cultivars is a significant time-consuming process owing to the three years of growth required for ginseng to flower. To shorten the ginseng breeding process, it is necessary to establish rapid progression through each generation. In this study, we examined it was possible to rapidly break ginseng seed dormancy using gibberellic acid ($GA_3$) treatment and alternating temperature. Methods and Results: Seeds were obtained from local variety. Seeds were treated with either $GA_3$ at a concentration of $100mg/{\ell} $, constant temperature ($-2^{\circ}C$ and $2^{\circ}C$), alternating temperature ($2^{\circ}C$ followed by $-2^{\circ}C$, followed by $2^{\circ}C$) or a combination $GA_3$ and temperature treatment. Following experimental treatment, seeds were sown into trays and placed in a greenhouse. Low germination rates were observed in seeds that did not receive $GA_3$ treatment, which were similar following $2^{\circ}C$ and $-2^{\circ}C$ constant temperature treatment. Germination rates increased in proportion to $GA_3$ and more so when combined with alternating temperature treatment. In additon, stem and leaf lengths of the resulting ginseng plants were increased following $GA_3$ treatment, although no synergistic effect was observed with alternating temperature treatment. Conclusions: These results suggest that a combination $GA_3$ and alternating temperature treatment enhances ginseng seed germination, which can contribute to shortening the time required to progress through a single ginseng generation for breeding.

• Journal of Sericultural and Entomological Science
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• v.30 no.2
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• pp.75-83
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• 1988

These experiments were carried out to define the rest period of mulberry by treating growth regulators in Taegu, Korea. Results obtained were as follows: It was recognized that the depth of rest in Taegu, Korea, was not deeper than that in Tokyo and Kagoshima, Japan. The rest of mulberry was begun at the end of September, subsequently became deeper through the first October into the late October and then turned gradually into quiescence by the beginning of November. Buds sprayed by gibberellic acid ($GA_3$) 10ppm and urea 0.5% were promoted to sprout, while naphthalene acetic acid (NAA) 0.02% inhibited strongly bud sprouting and abscisic acid (ABA) 20ppm had no effect on the rest of mulberry. Gibberellic acid 10ppm enhanced the rate of green color of bud after incubation for 10 days at $30^{\circ}C$. By the portion of mulberry stems, the depth of rest was different that the middle buds were less dormant than those lower. The optimal time required for the mulberry winter bud break is 15 days incubation at $30^{\circ}C$ as treated with $GA_3$.

• BMB Reports
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• v.32 no.1
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• pp.51-59
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• 1999

The Korean radish cationic peroxidase (KRCP) promoter, comprising nucleotides -471 to +704 relative to the transcriptional initiation site, was fused to the GUS gene and transformed to tobacco BY-2 cells. We examined how auxin (2,4-dichlorophenoxyacetic acid, 2,4-D), cytokinin (6-benzylaminopurine, BAP), gibberellic acid ($GA_3$), abscisic acid (ABA), methyl jasmonate (MeJA), and phosphatidic acid (PA) affect the GUS expression in the presence or absence of 2,4-D in a modified LS medium. Exogenous 2,4-D or BAP greatly decreased the GUS expression regulated by the KRCP promoter in a modified LS medium containing 0.2 mg/l 2,4-D. $GA_3$ increased the GUS expression and ABA completely reduced the inductive effect of $GA_3$. The GUS expression was also increased dose-dependently by plant defense regulators, MeJA and PA. In contrast to the above results, auxin deprivation from the modified LS medium increased the GUS expression after treatment with exogenous 2,4-D whereas BAP still greatly decreased the GUS expression dose-dependently. $GA_3$ or MeJA slightly decreased the GUS expression. The data suggest that auxin deprivation changes the sensitivity of the suspension cells to exogenous chemicals and that the regulation of the KRCP promoter by 2,4-D, $GA_3$, and MeJA is dependent on auxin, whereas the regulation by BAP is not. This study will be valuable for understanding the function and expression mode of the Korean radish cationic peroxidase in Korean radish.