• Korean Journal of Plant Tissue Culture
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• v.22 no.5
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• pp.267-271
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• 1995

To improve regeneration efficiency of Brassica campestris ssp. pekinensis (chinese cabbage) in vitro, the effect of ehtylene inhibitors [AgNO$_3$ and silver thiosulfate (STS)] and optimal age of explantse were investigated. On the effect of ethylene inhibitors either 100 $\mu$M of AgNO$_3$ or 5 $\mu$M of STS enhanced shoot regeneration from cotyledons when it was added in basal shoot induction media(MS salts, B5 vitamine, sucrose 2%, BA 2.0mg/L, NAA 1.0mg/L). But at higher concentrations, AgNO$_3$ induced abnormal shoots, and STS greatly reduced regeneration frequency. On the other hand, the maximum regeneration rate was obtained from the cotyledons taken from 3-day old seedlings. However there was no distinctive effect among the containers used for cultivation. The most optimal condition of root induction was a minimal Murashige and Skoog media containing 0.1 mg/L NAA. In order to induce bolting and flowering from in vitro regenerated chinese cabbage, the plant were healed at 4$^{\circ}C$ for weeks in a cold chamber. When they were planted in pots, the plane produced phenotipically normal flowers and seeds. The overall results suggest that ethylene inhibitors promote regeneration of shoot from cotyledons of chinese cabbage without alleviating fertility.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.433-440
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• 1994

The exposure of Clamydomonas reinhardtii to low temperatures resulted in an accumulation of cellular pyruvate that dissipated when the chilled cells returned to ambient temperature. The dissipation of pyruvate accumulation was accompanied by an increase in the production level of superoxide radicals $(O_2^-)$ in cells. The formation of $O_2^-$ at an excessive level during the post-chilling period was apparently countered by a substantial activation of superoxide dismutase (SOD). All these results are similar to those observed previously in rice seedlings subjected to the cold-treatment, implicating that a common mechanism is probably underlying for the primary processes of chilling injury both in higher plants and in algae. It was also observed that the activation of Mn-containing SOD contributes the major share in the increase of SOD activity of whole algal cells. Because Mn-SOD is present only in mitochondria, the observation corroborates the concept that the $O_2^-$ scavenging enzyme would be induced to cope with the cold treatment-caused adverse situation in mitochondria where the toxic active oxygen is produced at rates far exceeding the normal rate.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.72-77
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• 2007

This study was conducted to investigate the effect of functional cover film on oriental melon fruit quality under unheated plastic greenhouse cultivation in cold period. The 6 kind of films having different characteristics were covered at plastic greenhouses and oriental melon seedlings were cultivated at 2 regions of Seongju, respectively. The air-temperatures in plastic greenhouses of J-1 and J-2, having high infrared absorption rate, were about $2{\sim}5^{\circ}C$ higher than K-3. The contents of ${\beta}-carotene$ and sugar of fruit showed significant difference between functional and normal films. The sucrose, determining a sweetness during maturation, and soluble solids content of fruits cultivated in J-1, J-2, J-3, and K-1 were higher than those of K-2 and K-3. Ascorbic acid of fruits was highest in K-2 having low light transmission rate and thermo-keeping capacity. There was no significant difference in mineral content among all of cover films. These results indicated that the use of functional greenhouse covering films could improve fruit quality such as ${\beta}-carotene$ and sugar content of oriental melon.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.286-292
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• 1986

For the elucidation of saponin synthesis during ontogeny changes of ginsenosides and free sugars in seeds during stratification and seedlings in early growth stage were investigated with high performance liquid chrom-atography. Embryo plus endosperm at 40-day stratification showed 80% decrease of total saponin, disappear-ance of Rc, Rb$_2$ and Rb$_1$ and appearance of Rg$_3$ (probable) and 20-Glc-Rf (probable). Leaf ginsenoside F$_3$ was found not in fruit plup but seed and decreased during stratification. Both decomposition and synthesis of saponin seemed to occure during stratification. Ginsenosides in endosperm and embryo might be originated from fruit pulp by penetration. In seedling saponin appeared first in shoot and in root about one month later. Ginsenoside Rc, Rb$_2$, Rb$_1$ appeared in root at the last investigation (June 30) indicating normal saponin synthetic capacity of root. Saponin synthetic rate was twice in leaf than in root. Leaf ginsenoside F$_3$ was found in seedling root. Root saponin Rg$_3$ and 20-Glc-Rf were found in leaf and stem in seedling and decreased with growth suggesting that rate saponin is not such in certain growth stage. Total saponin content was negatively correlated with PT/PD in seeds and arial parts of seedling due to greater change of PD. than PT. Seed at 70days stratification showed high sucrose content. In seedling glucose was main sugar in stem all the while and sucrose in root at early stage while glucose, fructose and sucrose were found in leaf.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.571-575
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• 2014

'Dream Song' is a cultivar of Gypsophila paniculata developed by the Jeollabuk-do Agricultural Research & Extension Services in 2010 for cut-flower production. This hybrid was bred from 121 seedlings collected from an open-pollinated population of 'Gyp06-11'. It has novel morphological characteristics of upright plant type, lanceolate leaves, double florets with a few bright white-colored petals of obovate shape, truncate petal tips, and cup-shaped calyces. Furthermore 'Dream Song' has desirable cultivation characteristics including narrow branching angle, and moderate resistance to powdery mildew, thrips and leaf miners. Moreover it produces more primary branches, and longer internodes and flower stalks than reference cultivar 'Bristol Fairy' during summer cultivation in a subalpine area (500 m over the sea level). Flowering in 'Dream Song' is delayed by about 17 days as compared to 'Bristol Fairy'. 'Dream Song' produces normal flowers with 2 pistils and an average of 10.4 stamens, with fewer malformed flowers than 'Bristol Fairy'.

• Journal of Plant Biology
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• v.39 no.1
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• pp.71-77
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• 1996

Embryogenic callus was selected from callus induced from hypocotyl segment cultures of Daucus carota seedlings on MS basal medium supplemented with 1.0 mg/L 2,4-D. Cell clumps prepared from the embryogenic callus were transferred to MS medium without 2,4-D for somatic embryo development. Cotyledonary abnormalities were frequently observed on somatic embryos developed after the incubation of cell clumps in MS basal medium with 1.0 mg/L 2,4-D for one week and then subculture in the same medium but without 2.4-D for two weeks. The percentage of abnormalities was as follows: 5% one cotyledon, 21% three cotyledons, 6% four cotyledons, 5% five cotyledons, 0.2% six cotyledons and 1% trumpet-like cotyledons. On the other hand, the normal somatic embryo with two cotyledons appeared at 63%. The germination rate of somatic embryos was higher in two cotyledon somatic embryos than in multicotyledonary embryos. Trumpet-like somatic embryos did not germinate normally showing limited elongation and enlargement of roots and cotyledons without shoot development. From anatomical examination circular procambium in the root of somatic embryo began to branch around the middle regions of the hypocotyl which extended into the cotyledons through the cotyledonary nodes and the number of branched procambial strands in hypocotyl was equal to the number of cotyledons. Monocotyledonous somatic embryo always had larger cotyledon than that of somatic embryos with multicotyledons and had horseshoe-like cotyledons where the procambium was of the same structure.ucture.

• Korean Journal of Medicinal Crop Science
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• v.23 no.5
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• pp.379-384
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• 2015

Background : Considerable time and effort is required to develop new Panax ginseng varieties. Ginseng breeders have been developing techniques to shorten the breeding cycle to resolve this problem. In this study, we investigated the effects of adding $GA_3$ and alternating temperature (AT, $2^{\circ}C{\rightarrow}-2^{\circ}C{\rightarrow}2^{\circ}C$) on breaking bud dormancy in the varieties (Chungsun and Sunun) of ginseng root. Methods and Results : The $GA_3$ soaking treatment and AT were applied to one year old roots, which greatly accelerated the emergence of new buds. In one year old roots, new buds emerged from the 4th day post transplanting and after breaking dormancy with $GA_3$ and AT treatments. The emergence of new buds was completed within two weeks. The rate of bud emergence for Chungsun was 60% - 98% over 15 - 60 days after the AT and $GA_3$ treatments. The emergence rate of Sunun was 46% - 92%. Normal growth of the ginseng seedling was observed in spite of the early breaking of bud dormancy by combined $GA_3$ and AT treatments. Conclusions : $GA_3$ and AT treatments shortened the dormancy period and facilitated the stable emergence of ginseng seedlings. However, some plants suffered deformities and early sprouting owing to the combined $GA_3$ and AT treatments. Early sprouting was free from dormancy after leaf fall from the of aerial part of the plant.

• Molecules and Cells
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• v.41 no.5
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• pp.413-422
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• 2018

Soybean transgenic plants with ectopically expressed AtABF3 were produced by Agrobacterium-mediated transformation and investigated the effects of AtABF3 expression on drought and salt tolerance. Stable Agrobacterium-mediated soybean transformation was carried based on the half-seed method (Paz et al. 2006). The integration of the transgene was confirmed from the genomic DNA of transformed soybean plants using PCR and the copy number of transgene was determined by Southern blotting using leaf samples from $T_2$ seedlings. In addition to genomic integration, the expression of the transgenes was analyzed by RT-PCR and most of the transgenic lines expressed the transgenes introduced. The chosen two transgenic lines (line #2 and #9) for further experiment showed the substantial drought stress tolerance by surviving even at the end of the 20-day of drought treatment. And the positive relationship between the levels of AtABF3 gene expression and drought-tolerance was confirmed by qRT-PCR and drought tolerance test. The stronger drought tolerance of transgenic lines seemed to be resulted from physiological changes. Transgenic lines #2 and #9 showed ion leakage at a significantly lower level (P < 0.01) than ${\underline{n}}on-{\underline{t}}ransgenic$ (NT) control. In addition, the chlorophyll contents of the leaves of transgenic lines were significantly higher (P < 0.01). The results indicated that their enhanced drought tolerance was due to the prevention of cell membrane damage and maintenance of chlorophyll content. Water loss by transpiration also slowly proceeded in transgenic plants. In microscopic observation, higher stomata closure was confirmed in transgenic lines. Especially, line #9 had 56% of completely closed stomata whereas only 16% were completely open. In subsequent salt tolerance test, the apparently enhanced salt tolerance of transgenic lines was measured in ion leakage rate and chlorophyll contents. Finally, the agronomic characteristics of ectopically expressed AtABF3 transgenic plants ($T_2$) compared to NT plants under regular watering (every 4 days) or low rate of watering condition (every 10 days) was investigated. When watered regularly, the plant height of drought-tolerant line (#9) was shorter than NT plants. However, under the drought condition, total seed weight of line #9 was significantly higher than in NT plants (P < 0.01). Moreover, the pods of NT plants showed severe withering, and most of the pods failed to set normal seeds. All the evidences in the study clearly suggested that overexpression of the AtABF3 gene conferred drought and salt tolerance in major crop soybean, especially under the growth condition of low watering.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.25-32
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• 2014

The amount of TPH contaminated soil treated at off-site remediation facilities is ever increasing. For the recycle of the treated-soil on farmlands, it is necessary to restore biological and physico-chemical soil characteristics and to remove residual TPH in the soil by an economic polishing treatment method such as phytoremediation. In this study, a series of experiments was performed to select suitable plant species and to devise a proper planting method for the phyto-restoration of TPH-treated soil. Rye (Secale cereale) was selected as test species through a germination test, among 5 other plants. Five 7-day-old rye seedlings were planted in a plastic pot, 20 cm in height and 15 cm in diameter. The pot was filled with TPH-treated soil (residual TPH of 1,118 mg/kg) up to 15 cm, and upper 5 cm was filled with horticulture soil to prevent TPH toxic effects and to act as root growth zone. The planted pot was cultivated in a greenhouse for 38 days along with the control that rye planted in a normal soil and the blank with no plants. After 38 days, the above-ground biomass of rye in the TPH-treated soil was 30.6% less than that in the control, however, the photosynthetic activity of the leaf remained equal on both treatments. Soil DHA (dehydrogenase activity) increased 186 times in the rye treatment compared to 10.8 times in the blank. The gross TPH removal (%) in the planted soil and the blank soil was 34.5% and 18.4%, respectively, resulting in 16.1% increase of net TPH removal. Promotion of microbial activity by root exudate, increase in soil permeability and air ventilation as well as direct uptake and degradation by planted rye may have contributed to the higher TPH removal rate. Therefore, planting rye on the TPH-treated soil with the root growth zone method showed both the potential of restoring biological soil properties and the possibility of residual TPH removal that may allow the recycle of the treated soil to farmlands.

• Journal of Plant Biotechnology
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• v.40 no.2
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• pp.72-78
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• 2013

To establish an efficient protocol for plant regeneration of Brassica juncea L. Czern, the effects of explant types, explant ages and cytokinins on shoot regeneration were examined in this study. Shoot regeneration was markedly affected by the explant types used in the following order: cotyledon with petiole> hypocotyl> leaf with petiole> cotyledon> leaf. Five-day-old seedlings of cotyledon with petiole explants showed the maximum shoot regeneration frequency. Of the six cytokinins-6-${\gamma}$-${\gamma}$-Dimethylallylamino-purine (2-ip), 6-${\gamma}$-${\gamma}$-Dimethylallylamino-purine riboside (2-ip riboside), 6-Benzyl amino-purine (BAP), Thidiazuron (TDZ), Zeatin, Zeatin riboside-TDZ ($8{\mu}M$) was found to be the best cytokinin for shoot regeneration with the highest shoot induction frequency (80%) from cotyledon with petiole after 4 weeks. All the regenerated plantlets were developed well and they produced morphologically normal flowers.