• Journal of Integrative Natural Science
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• v.4 no.2
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• pp.113-120
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• 2011

Brassinosteroids (BRs) are plant steroid hormones that play essential roles in growth and development. Mutations in BR-signaling pathways cause defective in growth and development like dwarfism, male sterility, abnormal vascular development and photomorphogenesis. Transition from vegetative to reproductive growth is a critical phase change in the development of a flowering plant. In a screen of activation-tagged Arabidopsis, we identified a mutant named abz126 that displayed longer hypocotyls when grown in the dark on MS media containing brassinazole (Brz), an inhibitor of BRs biosynthesis. We have cloned the mutant locus using adapter ligation PCR walking and identified that a single T-DNA had been integrated into the ninth exon of the GIGANTEA (GI) gene, involved in controling flowering time. This insertion resulted in loss-of-function of the GI gene and caused the following phenotypes: long petioles, tall plant height, many rosette leaves and late flowering. RT-PCR assays on abz126 mutant showed that the T-DNA insertion in GIGANTEA led to the loss of mRNA expression of the GI gene. In the hormone dose response assay, abz126 mutant showed: 1) an insensitivity to paclobutrazole (PAC), 2) an altered response with 6-benzylaminopurine (BAP) and 3) insensitive to Brassinolide (BL). Based on these results, we propose that the late flowering and tall phenotypes displayed by the abz126 mutant are caused by a loss-of-function of the GI gene associated with brassinosteroid hormone signaling.

• Journal of Plant Biotechnology
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• v.47 no.1
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• pp.26-39
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• 2020

In maize, immature embryos (IEs) are highly regenerative explants most suitable for producing high frequencies of plantlet regeneration in vitro. Apart from media, explants, and hormones, genotypic variation also influences in vitro characters to a great extent. In the present study, IEs were used to study the distinctive effect of variation of size/stage and hormones in different genotypes on five in vitro characters viz., frequency of callus induction, growth rate of total callus, frequency of E. callus induction, and volume and number of regenerated plantlets. LS medium with different concentrations of 2,4-D (0.5, 1.5, 2.5, 4.0 and 5.0 mg/L) were used to study the former four in vitro characters, and medium with 6-benzylaminopurine and kinetin (0.5 mg/L, each) was used for plantlet regeneration. IEs of 1.0, 1.5, 2.0, 2.5 and 3.0 mm in size were isolated from four inbred lines viz., NM74C, NM81A, NM5883 and NM5884. Two-way ANOVA revealed that explant size and genotypes, as well as hormonal concentrations showed significant effects on in vitro characters. Two millimeter IEs were found to be suitable for in vitro cultures. LS medium with 1.5 mg/L 2,4-D and LS with BAP and Kn (0.5 mg/L, each) were found to be the best hormonal concentrations for callus induction, maintenance, and regeneration, respectively. Among the four genotypes, NM81A and NM5883 yielded more non-embryogenic and Type I E. calli. In contrast, NM74C and NM5884 yielded more highly regenerative Type II calli. Inbred line NM5884 was found to be the best among these four genotypes.

• Journal of Ecology and Environment
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• v.46 no.3
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• pp.218-242
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• 2022

Background: Promising specific growth regulators are employed in the tissue cultures of various bamboo species. Specific natural hardening mixtures support the acclimatization and adaptation of bamboo under protected cultivation. Results: The growth regulators like 2, 4-Dichlorophenoxyacetic acid (2, 4-D), Naphthaleneacetic Acid (NAA), Thidiazuron (TDZ), 6-Benzylaminopurine (BAP), Kinetin, Gelrite, Benzyl Adenine (BA), Indole Butyric Acid (IBA), Coumarin, Putrescine, Gibberellic acid (GA₃), Indole Acetic Acid (IAA) has been widely used for callus induction, root regeneration and imposing plant regeneration in various species of bamboo such as Bambusa spp. and Dendrocalamus spp. Different combinations of growth regulators and phytohormones have been used for regenerating some of the major bamboo species. Natural hardening materials such as cocopeat, vermicompost, perlite, cow dung, farmyard manure, compost, soil, garden soil, and humus soil have been recommended for the acclimatization and adaptation of bamboo species. Standard combinations of growth regulators and hardening mixtures have imposed tissue culture, acclimatization, and adaptation in major bamboo species. Conclusions: Bamboo contributes to soil fertility improvement and stabilization of the environment. Bamboo species are also involved in managing the biogeochemical cycle and have immense potential for carbon sequestration and human use. This paper aims to review the various growth regulators, natural mixtures, and defined media involved in regenerating major bamboo species through in vitro propagation. In addition, the ecological benefits of safeguarding the environment are also briefly discussed.

• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.129-135
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• 1997

Morphogenetic responses were investigated by culturing embryo and leaf explants of Korean wild type tea plant, Camellia sinensis (L.) O. Kuntze. Induction of direct somatic embryogenesis as well as adventitious and/or axillary shoots was obtained from mature zygotic embryo cultures on Murashige and Skoog (MS) basal medium having 5 to $20\mu\textrm{M}$cytokinin a lone. Morphogenetic response was decreased dramatically by the addition of auxins tested. One hundred percent of induced and isolated shoots formed roots after four weeks of culture on half-strength MS or quarter-strength Schenk and Hildebrandt (SH) media supplemented with $10\mu\textrm{M}$indole-3-butyric acid (IBA). Immature zygotic embryos were shown to be a suitable explant for embryogenic callus formation in the presence of 2, 4-dichlorophenoxyacetic acid(2, 4-D) in basal medium. Mature zygotic embryo originated leaves were used to test their ability for mophogenesis by incorporating plant growth regulators such as IBA, naphthyl-1-acetic acid (NAA), and 6-benzylaminopurine (BAP). Apparently, the morphogenetic responses of the cultured explant sources on the types and/or levels of plant growth regulators tested were observed visually.

• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.181-190
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• 2023

Domestic hop (Humulus lupulus L.) production has been suspended since the early 1990s due to foreign imports, but interest in local production is rising due to the recent craft beer boom in Korea. This study was conducted focusing on the development of growth characteristics and propagation technology for 6 introduced hop cultivars as a basic study for domestic hop production and breeding program. In the hop growth survey conducted in 2021 and 2022, the 5-year-old plants after planting generally showed a tendency to increase the height of strobile setting, strobile size, number and weight of strobile per hill compared to the 4-year-old plants. As a result of the experiment with hop vine cuttings, the average rooting rate of all cultivars was as high as 88% even in only water treatment that were not added with Atonik (Atonik, Arysta, Japan), a rooting agent. There were differences between cultivars in rooting length and rooting rate according to the Atonik treatment method. When checking the survival rate of the rooted cuttings seedlings after transplanting into the soil, it was confirmed that the survival rate of the cuttings in the tissue culture room was significantly lower than that of the cuttings in the greenhouse. However, in transplanting step, cutting plants from culture room condition was strongly inhibited plant growth because of changing environment conditions. As a results of tissue culture, the thidiazuron (TDZ) 1 ㎎/L treatment in the media generated 6 to 9 shoots/explant, while the 6-benzylaminopurine (BAP) 1 ㎎/L treatment generated only 1 to 2 shoots/explant. Therefore, it is more effective to culture by adding TDZ rather than BAP. These results indicated that the development of technology to manage stably after transplanting of cutting or micropropagating plants into potting soil is important for mass propagation of hops.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.278-285
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• 2008

An efficient transformation method for soybean [Glycine max (L.) Merr.] using meristematic tissues of germinating seeds has been established. The embryonic axes were excised from germinating seeds of Korean soybean cultivar, Iksannamulkong and 0.5-2 cm long segment containing meristematic tissues were prepared by cutting hypocotyl region. The explants were inoculated with Agrobacterium tumefaciens strain LBA4404 harboring a binary vector with the bar gene as a selectable marker gene and a ${\beta}-glucuronidase$ (GUSINT) reporter gene, and then co-cultured for 7 days on co-cultivation medium (CCM). The meristematic tissues were cultured on shoot induction medium (SIMP6) supplemented with 0.4 mg/l $N_6-benzylaminopurine$ (BAP) and 0.1 mg/l indolebutyric acid (IBA) in the presence of 6 mg/l L-phosphinotricin (PPT) for 2 weeks and the surviving explants were transferred to shoot elongation medium (SEMP6). Transformation was confirmed by Southern blot analysis and the transformation efficiencies ranged from 1.48 to 2.07%. The new modified transformation method was successfully implemented for obtaining several transgenic lines with SMV-CP gene. It is expected that this method could efficiently be used for the transformation of recalcitrant soybean cultivars.

• Journal of Life Science
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• v.12 no.6
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• pp.721-730
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• 2002

This study was carried out to select new pelleting binder and material for Welsh onion seeds. The optimum treatments of the various plant growth regulators to improve seed germination of the Welsh onion was also estimated. There were no significant effects of growth regulators on the germination percentage, but germination was faster according to the number of days to 50% of the final germination ($T_{50}$) and the mean number of days to germination (MDG) than those of the control. Germinability was increased when the seeds were soaked in gibberellic acid ($GA_3$) solution for 24hrs, even though there was no synergy effect on the germinability when $GA_3$ was mixed with 6-benzylaminopurine (BAP). The optimum treatment for improving germination of Welsh onion was observed when the tested seeds was soaked in 500 $\mu$M of $GA_3$ at $20^{\circ}C$ for 24hrs. Also, when the seeds soaked in the aforementioned treatment, the rate of germination was increased at lower temperature than at $20^{\circ}C$, the optimal temperature. The percentage and the speed of seed germination depended on the kinds of pelleting binder and their concentration. It showed that the higher the concentration of the binder for seeds pelleting, the lower the percentage of seed germination. Among the pelleting binder, polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) were the best binders for seed pelleting, because seed germination using those binder did not affect on the concentration of binder. On the other hand, Carboxymethy cellulose (CMC) and methyl cellulose (MC) severely inhibited the seed germination The germinability was also different arcording to the pelleting materials. Among the different 58 pelleting materials, kaoline alone, the mixture of bentonite and kaoline, the mixture of bentonite, calcium carbonate and diatomaceous earth #300 were found as the best pelleting materials for welsh onion seeds.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.72-77
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• 2017

This study was conducted to examine the effect by application method and concentration of plant growth regulator (PGR) on the growth and runner production of strawberry (Fragaria ${\times}$ ananassa Duch. cv. Maehyang) in a velno-type greenhouse. The seedlings of strawberry were transplanted in pot ($64{\times}27{\times}18cm$) filled with commercial mixed medium (Tosilee) on February 22nd, 2016. The 6-benzylaminopurine (6-BAP) was applied with foliar spray or drench, respectively as 900, 1,200 or $1,500mg{\cdot}L^{-1}$ (50 mL per plant) at 3 weeks after transplanting. Nutrient solution was sufficiently supplied by the drip irrigation as EC $0.65dS{\cdot}m^{-1}$ for rooting during 7 days. After rooting, the 450 mL nutrient solution supplied per pot twice a day (10 min). Plant height and crown diameter of 'Maehyang' mother plant appeared no significantly difference. The other growth characteristics, such as root length, number of primary roots, leaf length, leaf width, leaf area and fresh and dry weights of the shoot or root, were significantly the greatest in the control. And, the SPAD value of strawberry was the highest as 44.2 in the drench with $900mg{\cdot}L^{-1}$. The foiler spray was more effective in runner production than drench, and the number of runners appeared high values at the 900 and $1,500mg{\cdot}L^{-1}$. Whereas, the number of strawberry plantlets was effective in the drench. The results indicate that both growth and the number of runners of strawberry plant were the best achieved by foliar spray application at the $900mg{\cdot}L^{-1}$.