• Korean Journal of Medicinal Crop Science
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• v.17 no.1
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• pp.39-45
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• 2009

The effects of red, blue, and far-red light by illumination of light emitting diodes (LEDs) on growth, morphogenesis and eleutheroside contents of in vitro plantlets of Eleutherococcus senticosus were examined. As a control, plantlets were grown under a broad spectrum white fluorescent lamp (16/8 h illumination). The length of plantlets grown under the red/blue LEDs was taller than those under fluorescent lamps. Leaf area, root length and fresh weight of plantlets were highest under blue light compared to other kinds of light sources. Chlorophyll contents in plantlets grown under fluorescent lamps were higher than those in plantlets grown under LED illumination. Production of eleuthroside B and E in plantlets was highest under blue LED. However, production of eleuthroside E1 was highest under fluorescent lamps. These results suggest that plant growth and eleuthroside accumulation can be controlled by wave length of light under LED illumination system.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.431-437
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• 2017

Mulberry (Morus sp.) of the family Moraceae is very economically important in Asian countries including Korea, because its leaf and fruit have been commercially used in sericulture and horticultural industries. Therefore it is necessary to develop the optimal production system for rapid and cost-effective propagation of mulberry. Our studies focused on establishing an acclimatization method for the successful plantlet production of new cultivar 'Cheongsu' which was transferred ex vitro after in vitro culture. In particular, effect of abscisic acid (ABA) addition into the last subculture medium on plantlet response to subsequent ex vitro transfer and its growth was investigated. During acclimatization, stomatal conductance and transpiration rate of ABA-pretreated plantlets were significantly lower than those of non-treated plantlets. Net photosynthetic rate of ABA-pretreated plantlets decreased after ex vitro transfer but increased after 14 days, and it was mostly higher than that of non-treated plantlets. Moreover, relative water content as well as chlorophyll contents and its ratio were also higher in ABA-pretreated plantlets. On the other hand, proline was considerably higher than in control plantlets. After 1 month of ex vitro transfer, survival rate of ABA-pretreated plantlets was 85.6%, which increased by 29.1% in comparison with control (56.5%). More vigorous growth was also observed in ABA-pretreated plantlets. From these results, it was found that application of ABA to the last subculture medium could improve acclimatization and promote survival of mulberry plantlets after ex vitro transfer, inducing water stress tolerance and alleviating abiotic stresses.

• Korean Journal Plant Pathology
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• v.10 no.2
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• pp.140-143
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• 1994

Comparison of susceptibility of asparagus (Asparagus officinalis L.) seedlings and plantlets to different fusarial species was made to determine whether in vitro propagated asparagus plantlets can be used as a substitute for seedlings in histopathological study on the infection processes of Fusarium species to asparagus. Fusarium oxysporum was isolated most frequently (50% of the total) from lesions of root and crown rot of asparagus cultivated in the field followed by F. moniliforme (8.8% of the total) and F. solani (2.9% of the total). Plantlets and seedlings of all asparagus were susceptible to f. moniliforme and F. oxysporum isolates, but those were not susceptible to both avirulent F. oxysporum (AVFO) and F. solani in pathogenicity tests. Overall, there were no differences between seedlings and plantlets in the susceptibility to virulent fusarial infections. In vitro propagated asparagus plantlets, therefore, could be used as a substitute for seedlings in histopathological study on the infection processes of Fuasrium species to asparagus.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.298-301
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• 2005

Potato (Solamum tuberosum 'Dejima') plantlets were investigated on culture type and initial quantity of inoculation in bioreactor and survival rate by hydroponics for mass production. rode stems (1 to 1.5cm in length) of potato plantlets multiplied in vitro were grown for 3 weeks in liquid Murashige and Skoog (MS) medium with sucrose $30 g\; L^{-1}$. When plantlets (80-node inoculation) were raised in 10L balloon type bubble (BB) bioreactor, the healthiest growth of plantlets was obtained from explants cultured in ebb & flow culture with medium supplied periodically 12 times per day. The suitable inoculation quantity of 20L BB bioreactor was 120 pieces of stem segments (mean 2.2g fresh weight) in ebb & flow culture. Number of nodal shoot was eight on the average. In controlled culture room, survival rate of plantlets at 7 days after stem cutting was above $70\%$ when they were acclimatized by hydroponics grown in deep flow and solid medium culture. The highest survival rate of the stem cutting plantlets was in nutrient solution adjusted to EC $1.4dS{\cdot}m^{-1}$. Stem cutting plantlets through one culture could be obtained $670\~900$, when plantlets were grown in ebb & flow culture during 3 weeks using a 20L bioreactor with initial 120 pieces of nodal segments. 11 is possible In do mass production of seedlings cultured in bioreactor and hydroponics.

• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.273-276
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• 2001

In order to develop effective acclimatization methods for Aralia elata plantlets regenerated from somatic embryos, various acclimatizing conditions were compared regarding both survival rate and growth of the plantlets. The plantlets were transplanted into plastic boxes containing artificial soil in the presence of either several levels of MS liquid media, distilled water, 2% sucrose or 0.1% hyponex solution. They were then cultured by spraying of distilled water twice a week and maintained in the normal tissue culture room. Perlite was proved to be better than vermiculite on survival rate and growth of the plantlets. As the size of perlite (larger than 0.2 cm in diameter) increased, both the survival rate and growth of the plantlets improved. Among the various MS liquid media and different aqueous solutions tested, distilled water appeared to result in the best survival rate and growth. MS media were also effective in increasing survival rate and supporting growth when diluted to 1/4 and/or 1/8. The acclimatized plantlets could be transplanted directly onto the nursery bed and grown normally. The above results suggest that plantlets regenerated from somatic embryos of Aralia elata be effectively acclimatized using a plastic box containing perlite with distilled water treatment.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.110-118
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• 2016

We compared germination efficiency for somatic embryos (SE) of Liriodendron tulipifera using semi-solid (SS), temporary immersion bioreactors (TIB), and continuous immersion bioreactors (CIB) to produce vigorous plants. The bioreactors were designed to be immersed in liquid media with plantlets with an adjustable immersion time. TIB and CIB improved germination rates up to 80.86% and 95.21%, respectively, however, CIB produced more hyperhydric plantlets than TIB. The height of plantlets in TIB was significantly higher than for those in CIB. Fresh weights of plantlets grown in CIB of were significantly lower than for those grown in TIB. The lowest chlorophyll concentration was found in in vitro plantlets from CIB. We examined abnormally developed leaves, stems, and apical zones of in vitro plantlets that were produced in CIB. Among the three types, SS showed the highest stomatal density and the shortest stomatal length in in vitro plantlets. After acclimatization, plants from CIB exhibited the lowest values in biomass, such as height, root collar diameter, leaf fresh weight, leaf length, leaf width, petiole length, petiole diameter, and leaf area. Photosynthesis and transpiration rates of ex vitro plants were not significantly different among the three culture types, but stomatal conductance was higher in TIB than in the SS and CIB. Therefore, the results suggest that TIB is the preferable bioreactor to improve in vitro plantlet regeneration of L. tulipifera. TIB-originated plants showed higher growth rate than SS and CIB after transferring to soil.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.409-414
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• 2016

Background: The low survival rate of in vitro regenerated Panax ginseng plantlets after transfer to soil is the main obstacle for their successful micropropagation and molecular breeding. In most cases, young plantlets converted from somatic embryos are transferred to soil. Methods: In vitro thickened taproots, which were produced after prolonged culture of ginseng plantlets, were transferred to soil. Results: Taproot thickening of plantlets occurred near hypocotyl and primary roots. Elevated concentration of sucrose in the medium stimulated the root thickening of plantlets. Senescence of shoots occurred following the prolonged culture of plantlets. Once the leaves of plantlets senesced, the buds on taproots developed a dormant tendency. Gibberellic acid treatment was required for dormancy breaking of the buds. Analysis of endogenous abscisic acid revealed that the content of abscisic acid in taproots with senescent shoots was comparatively higher than that of taproots with green shoots. Thickened taproots were transferred to soil, followed by exposure to gibberellic acid or a cold temperature of $2^{\circ}C$ for 4 mo. Cold treatment of roots at $2^{\circ}C$ for 4 mo resulted in bud sprouting in 84% of roots. Spraying of 100 mg/L gibberellic acid also induced the bud sprouting in 81% roots. Conclusion: Soil transfer of dormant taproots of P. ginseng has advantages since they do not require an acclimatization procedure, humidity control of plants, and photoautotrophic growth, and a high soil survival rate was attained.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.60-65
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• 2017

This study was conducted to dentify the optimum plantlet type of 'Solara' potatoes (Solanum tuberosum L.) for growth in an aeroponics system. Plantlets of 'Solara' were transplanted on March 16, 2015 in a greenhouse, and growth and yield characteristics were investigated at 70 and 78 days after transplanting, respectively. Stem length was shorter in plantlet of 15-day-old stem cuttings and acclimatization of culture, and the stem length of plantlets of stem cuttings tended to increase with increasing stem cutting age. The fresh weight of plants was the highest in the plantlets of 40-day-old stem cuttings and the lowest in non-rooted stem cuttings and acclimatization of culture. The highest number of first stolons was obtained in 35-day-old stem cuttings. The number of second stolons was the highest in plantlets of 35-day-old stem cuttings, acclimatization of culture, and 30- day-old stem cuttings. The total number of tubers was higher in plantlets of 35-day-old stem cuttings and acclimatization of culture, and the number of tubers above 3 g was the highest in plantlets of 35-day-old stem cuttings. The weight of tubers above 3 g was the heaviest in plantlets of 35-day-old stem cuttings(1,947 g per 10 plants), followed by plantlets of 30-day-old stem cuttings. These results indicate that plantlets of 30 to 35-day-old stem cuttings could be the best for production of 'Solara' potato tubers in an aeroponics system.

• Journal of Forest and Environmental Science
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• v.23 no.1
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• pp.5-9
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• 2007

Zygotic embryos just after harvest of seeds were immature globular to heart stage. Maturation of zygotic embryos rapidly proceed when zygotic embryos together with small excised parts of endosperm were cultured on 1/3-strength MS solid medium with 2% sucrose, and the zygotic embryos were germinated within two months. Embryogenic callus was formed from the excised segments of germinating zygotic embryos of Eleutherococcus pedunclus on Murashige and Skoog (MS) medium with $4.5{\mu}M$ 2,4-D. The embryogenic callus formation occurred at a low frequency (less than 7%) from hypocotyl segments. The embryogenic calli were maintained on the same medium as primary medium. High frequency somatic embryogenesis was obtained after the cells were transferred to medium lacking 2,4-D. Cotyledonary embryos were germinated and converted into plantlets on medium with $20{\mu}M$ $GA_3$. Embryogenic callus and somatic embryos were produced spontaneously on the surfaces of roots and/or hypocotyls of plantlets. The frequency of embryogenic callus formation was 85% in roots and 34% in hypocotyls. Therefore maintain of cell lines performed very easily. Plantlets with developed epicotyls at more than 3 cm acclimatized at high frequency (89%). While plantlets with small epicotyls (less than 1 cm) were acclimatized at low rate (32%). The soil survived plantlets produced new sprouts after over wintering in the field.

• Journal of Forest and Environmental Science
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• v.35 no.1
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• pp.54-60
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• 2019

Plant tissue culture techniques offer quick methods of regeneration of plants of medicinal importance but the survival chances of such plants are always questionable when shifted to the in vivo conditions. The present study enumerates the micromorphological developments in the leaves of in vitro regenerated and field transferred plantlets of Oldenlandia umbellata. The leaves developed in vitro after $4^{th}$ subcultures of multiplication phase and after 6 weeks of field transferred plants were used. Statistically significant differences in the number of stomata, veins, raphides, crystals and trichome density per square mm were observed. The improvements in stomatal apparatus and density (decreased from 41.85 to 32.20), developments in leaf architectural parameters and emergence of defense mechanism through increased numbers of raphides (8 to 15), crystals and trichomes (13.5 to 18.2) proved acclimation of tissue culture raised plantlets from in vitro to the in vivo environments lead to 100 % success in field establishment of the plantlets. The in vitro induced foliar abnormalities (changes in stomata, venation pattern, vein density, trichomes, crystals etc.) were repaired while hardening of plantlets in the greenhouse and finally in the field. The observed micromorphological response of leaves under altered environmental conditions could help in determination of proper stage of field transfer and prediction of survival percentage of in vitro regenerated O. umbellata plantlets.