• Journal of Plant Biotechnology
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• v.34 no.4
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• pp.331-338
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• 2007

One-node stem pieces ca. 1 cm in length containing a axillary bud and a fully expanded leaf were obtained from it in vitro plants of potato (Solanum tuberosum L.). Leaves were removed and the nodes were cultured on the MS medium to investigate the effects of temperature, day length, sucrose, and CCC in microtuber formation and development. The fresh weight of microtubers after 80 days increased significantly at 8% sucrose and $20^{\circ}C$ compared with $28^{\circ}C$. The tuberization and development were reduced at $28^{\circ}C$ except short-day treatment of 8 hours at 8% sucrose. The fresh weight and diameter were increased on the culture medium added CCC 500 mg/L. The potato tuberization was promoted under short daylength, and it showed great effect by treatment with the CCC. Though the tuberization was promoted at low temperature of $20^{\circ}C$ in a histologic change of an axillary bud part cell of a potato, the cells were able to observe the swelling growth. Swelling growth of tissue was stimulated in the darkness and was more remarkable by addition of CCC. In particular, in the visual ratio of cell division for each position in the tissue, the cortex part showed larger ratio of cell expansion than that of the pith part. The effect of CCC was identified at 8% sucrose in the darkness. The effect of CCC was not showed in sucrose 3% under long daylength of 16 hours. As a result, the fact of a substance with AGPase important for starch composition was certified by the result with the inclose of AGPase activity on high concentration of sucrose, CCC, and dark treatment by which tuber formation and development are promoted.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.4
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• pp.279-288
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• 2007

In the present study, we focused on stem cells in the dental papilla of the tooth germ. The tooth germ, sometimes called the tooth bud, is the primordial structure from which a tooth is formed. The tooth germ consists of the enamel organ, the dental papilla, and the dental follicle. The dental papilla lies below a cellular aggregation of the enamel organ. Mesenchymal cells within the dental papilla are responsible for formation of dentin and pulp of a tooth. Tooth germ disappears as a tooth is formed, but that of a third molar stays in the jawbone of a human until the age of 10 to 16, because third molars grow slowly. Impacted third molar tooth germs from young adults are sometimes extracted for orthodontic treatment. In the present study, we evaluated the osteogenic activity and mineralization of cultured human dental papilla-derived cells. Dental papillas were harvested from mandible during surgical extraction of lower impacted third molar from 3 patients aged 13-15 years. After passage 3, the dental papilla-derived cells were trypsinized and subsequently suspended in the osteogenic induction DMEM medium supplemented with 10% fetal bovine serum, 50 g/ml L-ascorbic acid 2-phosphate, 10 nM dexamethasone and 10 mM -glycerophosphate at a density of $1\;{\times}10^6\;cells/dish$ in a 100-mm culture dish. The dental papilla-derived cells were then cultured for 6 weeks and the medium was changes every 3 days during the incubation period. Dental papilla-derived cells showed positive alkaline phosphatase (ALP) staining during 42 days of culture period. The formation of ALP stain showed its maximal manifestation at day 7 of culture period, then decreased in intensity during the culture period. ALP mRNA level was largely elevated at 1 weeks and gradually decreased with culture time. Osteocalcin mRNA expression appeared at day 14 in culture, after that its expression continuously increased in a time-dependent manner up to day 28. The expression remained constant thereafter. Runx2 expression appeared at day 7 with no detection thereafter. Von Kossa-positive mineralization nodules were first present at day 14 in culture followed by an increased number of positive nodules during the entire duration of the culture period. Osteocalcin secretion was detectable in the culture medium from 1 week. The secretion of osteocalcin from dental papilla-derived cells into the medium greatly increased after 3 weeks although it showed a shallow increase by then. In conclusion, our study showed that cultured human dental papilla-derived cells differentiated into active osteoblastic cells that were involved in synthesis of bone matrix and the subsequent mineralization of the matrix.

• Korean Journal of Medicinal Crop Science
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• v.4 no.2
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• pp.119-125
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• 1996

To improve the efficiency of mass propagation in vitro of Fritillaria thunbergii, bulb scale and nodes were cultured in LS medium supplemented with the combination of 2, 4-D and kinetin or NAA and BA. The number and size of bulb, the number of adventitious shoot, the ratio of callus formation, rooting, and the effects of light and dark on the culture, plant regeneration from calli, and the gelling substances were investigated. The combination of 2, 4-D and kinetin in media was more effective than the media of NAA and BA for the bulblet formation. The media supplemented with 2 mg/L 2, 4-D and 1 mg/L kinetin, $1{\sim}2\;mg/L$ 2, 4-D without kinetin and $1{\sim}3\;mg/L$ BAA only were effective in the adventitious shoot development. Callus formation and root formation, respectively were effective in the medium supplemented with 2mg/L 2, 4-D and 1mg/L kinetin. In bulb formation, the medium with 5 mg/L kinetin was effective, and the most of bulbs were formed from the axillary bud of node part. In bulb formation, shoot growth, callus and root formation, the light culture for 16 hours per day was better than that in the dark culture. Bulb was nicely formed in the medium with 0. 2 mg/L 2, 4-D, 1 mg/L kinetin. The medium without hormone was most effective for plant regeneration. The phytagel was more effective than agar in the medium as the gelling agent.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.382-389
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• 2005

This study was conducted to establish the system of effective in vitro propagation by various explant sources culture of Bippeastrum hybridum Hort, 'Dazzler'. We tested the effects of optimal explant source, plant growth regulators on bulblet formation and plant regeneration. Callus was readily produced on the different tissues excised from floral buds whereas, bulbs and shoots were formed only on pedicel explants as compared with anthers, styles and ovaries. Pedicel is the best optimal explant for in vitro propagation. Two distinct pathways, organogenesis through callus and direct bulblet formation, could be recognized in pedicel culture. Up to the $80-100\%$ of bulblet formation and shoot organogenesis from the pedicel in fifteen days before anthesis were effectively induced by MS medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BA. Plantlet regeneration was successfully achieved from pedicel-derived callus, via shoot bud induction or direct bulblet formation. The bulblets with blooming flower were produced within 2 years.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.573-578
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• 2012

A total of eleven Chinese cabbage accessions were used for microspore culture and were grown to take basal data. Based on the collected data, breeding materials were chosen to develop new improved Chinese cabbage cultivars. The range of microspore-derived embryoid taken from flower buds was 1.6 to 35.4 embryoids. The embryoids from IT26110 and IT26153 among the Chinese cabbages were more than 34 per flower bud. The viability rate after cold treatment was low from 0.2 to 11.7%. The range of fertility rate was 7.7 to 58.8% in general but the IT26118, IT26122, IT26128, IT26130, and IT26164 were more than 50%. The result of their seed production ability by selfing was 11.9 seeds per siliqua in IT26128 while the others were less than 10 seeds. In the microspore culture using parents of different hereditary, the number of embryoids, the number of plants, the rate of fertility and their pure seed production ability appeared to be very different in doubled haploid lines obtained from fertile plants of Chinese cabbage.

• The Korean Journal of Zoology
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• v.33 no.3
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• pp.310-321
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• 1990

To establish the in vitro culture system and quantitation for chondrogenesis, and to investigate the relationship between cell aggregation and chondrogenesis, chick limb bud mesenchymal cells of Hamburger-Hamilton stage 23/24 were micromass cultured in various cell densities. The chondrogenesis was assayed based on checking the alcian blue-stained nodule numbers, the amount of alcian blue extraded, the change in cell numbers, the rate of [35 S] sulfate incorporation and expression of type II collagen. Mesenchymal cells plated with an initial density of high (1 x 107 cells/ml)- and intermediates (5. $\times$ 106 cells/ml)-density were differentiated into cartilage. On the other hand, the cells of low density (2 x 106 cells/mi, 5 $\times$ 105 cells/ml) of stage 23/24 cells and the stage 18/19 cells in three kinds of cell density did not differentiate into cartilage even though the cells formed an aggregated core at the center of cultured mass. From these results and others obtained in this study, it can be stated that the stage 23/24 mesenchymal cells are likely to pass over the aggregation step and have the potentiality to differentiate into chondrocytes. Thus chondrogenesis in vitro can be observed when mesenchymal cells are plated over the threshold density of 5 $\times$ 106 cells/ml. Hyaluronidase (HAase) activity was relatively constant throughout the culture, suggesting that the role of HAase may not be important for the cells of stage 23/24.

• Korean Journal of Medicinal Crop Science
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• v.3 no.1
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• pp.40-44
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• 1995

This study was aimed to mutant induction in Gentiana scabra BUNGE through the tissue culture techniques and comparison of gentiopicroside content in each mutant plants derived from tissue culture. In order to induce the mutants of Gentiam scabra, seed, apical and lateral bud were soaked in $NaN_3$, EMS and MNU solutions and cultured on MS basal medium containing 0.5mg/l NAA, BA $NaN_3$, MNU-treated buds survived about 50% but not survived in EMS treatment. Seed germination rate was extremely low in EMS and MNU treatments but various types of mutant plantlets were obtained by those treatments. 63% of elongated type and 37% of dwarf type were obtained from tissue culture treated by various mutagen. Gentiopicroside contents of regenerated plantlets was analyzed. Root of dwarf type contained more gentiopicroside(1.383%) than that of elongation type (0.083%).

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.104-110
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• 2015

This study was conducted for 3 years in an apple orchard to investigate the efficacy of the glufosinate-ammonium (GFA) SL for weed control in comparison to non-woven fabric mulch, sod culture and machinery cutting treatments. Glufosinate-ammonium SL 18% was applied with 2 to 3 times, and the extents of injury caused by the different weed control methods were also investigated during the 3 years. The highest level of weed control was obtained by glufosinate-ammonium 3 times spray (98.7%), followed by machinery cutting (95.1%), glufosinate-ammonium 2 times spray (81.5%) and natural sod culture (5.8%). Amounts of fruit production in three times application of glufosinate-ammonium 540 g a.i. $ha^{-1}$, twice application of GFA, machinery cutting, non-woven fabric processing, sod culture and untreated control were 27.2, 26.2, 25.3, 24.1, 20.4 and 13.3 kg, respectively. There was no toxicity symptom of glufosinate-ammonium on the whole tree such as fruit, bud, trunk, branch and flower during the 3 years.

• Horticultural Science & Technology
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• v.31 no.5
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• pp.648-651
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• 2013

A new cultivar 'Daewang' strawberry was developed by the National Institute of Horticultural & Herbal Science for forcing culture in 2010. The cultivar 'Daewang' was originated from the cross between 'Maehyang', a high firmness cultivar and 'Wongyo 3111', a high sugar content in 2006. The cultivar shows erect plant type, vigorous growth habit, early flower bud differentiation with 12-15 flowers per cluster from planting on healthy nursery. Fruits of 'Daewang' are conical type having a bright red skin color, and 16-17 g in an average weight. 'Daewang' is suitable for forcing culture as time required for dormancy breaking ranged between 50 and 100 hours. This cultivar has excellent taste for high sugar/acid ratio as sugar content of $11.1^{\circ}Brix$, acidity of 0.39% with abundant texture and can be harvested by late spring because the fruit firmness of 'Daewang' was $18.2g{\cdot}mm^{-2}$ that was about $7.9g{\cdot}mm^{-2}$ higher than $10.3g{\cdot}mm^{-2}$ of 'Akihime' cultivar. But although total yield is not significantly different from 'Akihime' cultivar, its marketable yield is remarkably higher than that of 'Akihime' cultivar. Disease and pest resistance of 'Daewang' have a tendency to sensitive powdery mildew, anthracnose and spotted spider.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.31-35
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• 2010

In this experiment, the effects on the growth and the quality of cut flowers of chrysanthemum 'Jinba' were mainly concerned depending on cultural methods between the pinching and the non-pinching. According to the results, the sufficient period of the vegetative growth was necessary to enter the flower bud differentiation in case of the non-pinching cultivation whereas it was not the case on the pinching. As compared with the pinching, the non-pinching showed 10% higher in the flowering ratio after flower bud differentiation. The flowering ratio of the non-pinching exceeded more than 95% but the pinching showed below 95% of the flowering ratio after flower bud differentiation. Comparing the number of cutting flowers between pinching and non-pinching, it was the non-pinching that showed the production of the first grade cutting flowers about 5 weeks faster than that of the pinching. It seem to be possible that harvesting time and growing period could be shortened. In the non-pinching growing region, above third-grading marketable cut flowers was 100% regardless of planting time. On the contrary, the pinching method showed 84.7% of marketable cutting flowers at first week from the planting, followed by 64.3% at second week, 18.8% at third week, and 2.6% at fourth week. Marketability of cutting flowers indicates that were planted by the pinching is very poor. When draw a comparison between the fourth-week planting of the non-pinching with the first-week planting of the pinching, the non-pinching could cut the growing period 38 days shorter than the pinching and the marketability was better. These results indicate that the non-pinching method can shorten the growing period and harvesting time compared to the pinching and it also resulted in reduction of cost and rapid production of the cutting flowers.