• The Korean Journal of Ecology
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• v.16 no.1
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• pp.63-74
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• 1993

The ecotypic variation of Phragmites communis Trin. was studied from Aug. 1989 to March 1992 in three populations of salt marsh, estuary and fresh water areas of the western coastal regions in Korea. The length growth and aboveground total dry weight of Phragmites communis Trin. From three habitates were measured monthly and the seeds from them collected. Chlorophyll contents, bud number and width of Phragmites communis Trin. populations after their seeds were sown in seedbeds, and the growth of seedlings according to salt contents were also determined. The results lare summarized as follows: The height and basal diameter of shoot, leaf length and width, and total dry weight of Phragmites communis Trin. were very different from each other according to their natural habitats. The bud number of seeds was increased as sample sites moved from estuary to fresh water areas and salt marsh. The but the bud diameter turned out to be in reverse proportion to the bud number. The chlorophyll content of the population from fresh water was $8.6901{\mu}g/ml$, whereas that from estuary and salt marsh was $9.61801{\mu}g/ml$ and $10.3160{\mu}g/ml$, respectively. The average length growth and total dry weight of seedlings grown at different salt contents were compared. Those of fresh water area decreased at salt contents lower than 0.5% in culture solution and those of estuary at higher than 0.5%, but the population of salt marsh was shown to be capable of sustaining itself at 1.0%. All of these results suggested that the populations of Phragmites communis Trin. in the western coastal regions of Korea have undergone ecotypic variations: fresh water type, estuary type and salt marsh type.

• Tuberculosis and Respiratory Diseases
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• v.80 no.1
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• pp.60-68
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• 2017

Background: Mucus hypersecretion from airway epithelium is a characteristic feature of airway inflammatory diseases. Tumor necrosis factor ${\alpha}$ (TNF-${\alpha}$) regulates mucin synthesis. Glucocorticoids including mometasone fuorate (MF) have been used to attenuate airway inflammation. However, effects of MF on mucin production have not been reported. Methods: Effects of MF and budesonide (BUD) on the phorbol-12-myristate-13-acetate (PMA)-induction of mucin and TNF-${\alpha}$ in human airway epithelial cells (NCI-H292) were investigated in the present study. Confluent NCI-H292 cells were pretreated with PMA (200 nM) for 2 hours. Subsequently, the cells were stimulated with MF (1-500 ng/mL) or BUD (21.5 ng/mL) for 8 hours. Dexamethasone ($1{\mu}g/mL$) was used as the positive control. Real-time polymerase chain reaction was used to determine MUC2 and MUC5AC mRNA levels. The level of total mucin, MUC2, MUC5AC, and TNF-${\alpha}$ in culture supernatants were measured using enzyme-linked immunosorbent assay. Results: MF and BUD significantly suppressed MUC2 and MUC5AC gene expression in PMA-stimulated NCI-H292 cells. The inhibitory effects of the two steroid drugs were also observed in the production of total mucin, MUC2 and MUC5AC proteins, and TNF-${\alpha}$. Conclusion: Our findings demonstrated that MF and BUD attenuated mucin and TNF-${\alpha}$ production in PMA-induced human airway epithelial cells.

• Korean Journal of Organic Agriculture
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• v.18 no.4
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• pp.549-557
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• 2010

This study was established on which germanium (Ge), known as one of the functional nutrients, treatment is the most effective method for increasing Ge uptake and contributing flowering development in the pruned branches in the winter. Ge treatment included foliar application, soil fertigation, trunk injection, and the three-combined application. Ge concentration in the pruned branches was greater on the three-combined treated trees, and Ge treated branches had greater Ge concentrations than the control. Pruned branches grown in the solution culture had greater bud weight and bud scale number on the Ge treated trees than the control. Ge treatments increased flowering per branch and flower number per bud as well as improved resistance of the freezing temperature damage. Overall, there were no consistent results of all the variables by the Ge application methods.

• Journal of Plant Biotechnology
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• v.6 no.2
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• pp.97-102
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• 2004

This study was carried out to establish The regeneration of healthy seedlings from the nodal segment culture of Chinese yam (Dioscorea opposita cv. Danma), cultivated in Korea. Different explants such as leaves, petioles, roots and nodal pieces, excised from the in vitro grown seedlings of Chinese yam, were cultured on MS medium supplemented with various combinations of growth regulators. All the growth regulators used induced plantlet regeneration from the nodal segments at a high frequency, while there was no induction of shoot or callus from leaf, petiole or root tissues. The medium supplemented with 0.01mg/L NAA, 0.5mg/L BA, 0.5-1.0mg/L kinetin and without plant growth regulator was effective for shoot development of buds from the nodal segment culture. The concentration of BA and NAA was an important factor in the bud induction of buds from the nodal segments of Chinese yam. Nodal segments cultured on the medium containing 1.0mg/L NAA and 0.5-1.0mg/L BA gave the best response to bud formation. The addition of GA$_3$ to the culture medium suppressed shoot induction and growth, while it increased microtuber formation. The shoot growth and microtuber formation were also affected by medium strength and solidity. The MS basal medium containing 1 g/L gelrite was suitable for microtuber formation from the nodal segment of Chinese yam.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.360-364
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• 2006

The gametophytes of Cyrtomium falcatum and Cyrtomium caryoptideum var. coreanum arising from spores were mechanically homogenized and cultured In vitro, to study their gametophyte ontogeny and sporophyte development. Homogenized gametophytic tissues formed as one-dimensional filaments after 2 weeks in culture and then glowed into blanched gamatophytes after 4 weeks. After 6 weeks, which were developed to two dimensional plates with apical notch and meristem in central zone. After 8 weeks in culture, apomictic buds were formed on the midribs without archegonium formation and these buds developed to sporophytes after 10 weeks in culture. Flow cytometric analysis of gametophytes and apomictic sporophytes revealed that both forms had the same ploidy level in C. falcatum and C. caryoptideum vu. coreanum, respectively. This is to certify that C. caryoptideum var. coreanum was an apomictic fern as well as C. falcatum.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.04a
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• pp.6-9
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• 2005

Plant biotechnology involving genetic modification has been rather controversial. However, the major issues related to safety are being addressed by continued improvements in technology. Some of the related facts will be highlighted to set the tone for a scientific discussion on the possibilities of using the technology for crop improvement. Our main research interest is to understand the molecular regulation of shoot bud regeneration in plant tissue culture, which is essential for crop improvement by biotechnology. We have isolated and characterized some genes that are associated with adventitious shoot regeneration. These include a MADS-box cDNA (PkMADS1) from paulownia kawakamii, which regulates vegetative shoot development and in vitro shoot regeneration from leaf explants. Another gene we have characterized from petunia codesfor a cytokinin binding protein (PETCBP). Preliminary functional analysis of this gene indicated that this also affects adventitious shoot bud initiation. Also, the antisense suppression of this gene in petunia causedexcessive branching. Results from our work and selected other publications will be used to highlight the possibilities of manipulation of such genes to improve crop species.

• FLOWER RESEARCH JOURNAL
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• v.16 no.4
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• pp.239-246
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• 2008

This study was conducted to establishment of in vitro micropropagation through induction of multiple shoots from axillary bud culture in Calanthe discolor Lindl. Shoots initiation from axillary bud was the most effective on half strength MS medium supplemented with $0.5mg{\cdot}L^{-1}$ NAA and $2.0mg{\cdot}L^{-1}$ TDZ during four weeks of dark culture followed by culture under a 16-h photoperiod. Multiple shoots (12.5 shoots per explant) were proliferated on half strength MS medium containing $4.0mg{\cdot}L^{-1}$ TDZ and $2.0mg{\cdot}L^{-1}$ IBA. On the other hands, the abnormally emerged shoots during the multiple shoot proliferation stage were recovered to normal shoots on half strength MS hormone free medium. Multiple shoots were well elongated and rooted on half strength MS medium with $0.1mg{\cdot}L^{-1}$ NAA. The plantlets were acclimatized up to 100% on TKS substrate after pretreating with $10mg{\cdot}L^{-1}$ NAA for 30 min. and these plantlets showed good growth as well.

• Korean Journal of Plant Tissue Culture
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• v.21 no.3
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• pp.173-176
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• 1994

Stem and petiol explants of peony culture turned to brownish black soon after placing onto medium and degenerated to death. Disroloration was caused mainly by ferrous and calcium cloride. Nitrate was a main factor for the death of culture. The culture damage was increased with the increment of the medium salt strength. A few latent axillary buds were elongated to shoots without forming callus.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.540-544
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• 2010

The nursery plant quality and flower bud induction of new strawberry cultivars, 'Maehyang' and 'Seolhyang' in forcing culture were evaluated in the highland and lowland region. In order to produce daughter plants, the new cultivars were grown in the open field located at both highland (Daekwallyung, above 800 m sea level) and lowland (Gangneung, above 20 m sea level) region, respectively. The average air temperature at highland during nursery plant propagation period was $5.3^{\circ}C$ lower than those at lowland. The number of daughter plants produced at lowland was 2 times as high as those of highland, presumably due to the higher air temperature. Anthracnose incidence rates of runner plants produced at lowland were 4 to 7% as high as those in highland. Mean temperature in the highland ($23.5^{\circ}C$) during flower bud differentiation treatment was $5.1^{\circ}C$ lower than that in the lowland ($28.6^{\circ}C$). Seedlings produced in highland showed higher C/N ratio and lower T/R ratio compared to those produced in lowland. The average flower bud formation date of the daughter plants grown in highland were advanced by 30 days compared to the date in lowland. Accordingly, highland was supposed to be appropriate region for raising seedlings in forcing culture of the new strawberry cultivars of 'Maehyang' and 'Seolhyang'.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.189-194
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• 2020

Daphne pseudomezereum var. koreana is native to Korea and is distributedin Kangwon-do, Jeollabuk do, and Gyeongsang-do. This economically valuable species has experienced a dramatic decrease in natural habitat due to climate change and is difficult to cultivate. In this study, we investigate a mass propagation method for D. pseudomezereum through in vitro culture and genetic resource preservation.WPM medium was better than the MS medium for shoot growth. As a result, we compared the shoot number and length of apical (W/AP) and non-apical shoots (W0/AP) with BA and GA₃ treatments in WPM medium. Their shoots and length grew well in both BA 8ìM + GA₃8ìM-treated apical shoot and without-apical shoot. NAA did not effectively induce rooting of the in vitro plantlet.