• Plant Biotechnology Reports
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• v.3 no.4
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• pp.333-340
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• 2009

Developmental anomalies in the plumule meristem of peanut (Arachis hypogaea L.) somatic embryos resulted in poor shoot differentiation and reduced plant recovery. Existing meristems with caulogenic potential have never been tested for embryogenesis in peanut. The present experiment was designed to test the mature zygotic embryo axis derived plumule with three meristems for somatic embryogenesis. Embryogenic masses and embryos developed from the caulogenic meristems in the axils. Exposure of 2 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation temporarily which then regained the ability to form the shoot on withdrawal of 2,4-D. Exposure of 4 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation irreversibly. No shoot formation was noted from the tips in any of the cultures which were in secondary medium with $13.6{\mu}M$ 2,4-D. Development of somatic embryos directly from axillary meristems was confirmed histologically. Conversion frequency of these embryos was 11%. Thus, in this report, we describe a method to obtain somatic embryos from the determined organogenic buds of the axillary meristem, by culturing the nodal explant vertically on embryo induction medium. It also displays the possibility of obtaining both embryogenic and organogenic potential in two parts of the same explant simultaneously. The possibility of extending this approach for genetic transformation in in vivo system through direct DNA delivery or Agrobacterium injection in meristems can also be explored. Using Agrobacterium rhizogenes, we have demonstrated the possibility of gene transfer in the axillary meristems of seed-derived plumule explant.

• Korean Journal of Plant Resources
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• v.33 no.6
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• pp.675-681
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• 2020

This study describes an efficient and stable droplet vitrification following cryopreservation of strawberry shoot tip (Fragaria × ananassa Duch.) accessions 'Massey' and 'MDUS3816'. The shoot tips were precultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3-0.7M). Precultured explants were osmoprotected with loading solution (LS, C4) containing 17.5% glycerol and 17.5% sucrose for 40 min and exposed to dehydration solution (B1) containing 50% glycerol and 50% sucrose for 40 min at 25oC. Subsequently, the explants were transferred onto droplets containing 2.5 µL PVS3 on sterilized aluminum foils (4 cm× 0.5 cm) prior to direct immersion in liquid nitrogen (LN) for 1 h. The highest regrowth rate (%) in both the cultivars was obtained when the shoot tips were precultured with 0.3M sucrose for 30 h + 0.5M sucrose for 16 h at 25oC. The cryopreserved shoots tips exhibited 57.8 % recovery rate by culturing in NH₄NO₃-free MS medium supplemented with 3% sucrose, 1.0 g/L casein, 1.0mg/L GA₃, and 0.5 mg/L BA for 5 weeks and in MS medium supplemented with 0.5 mg/L GA₃ for 8 weeks. Variation was not observed in both of ploidy analysis and morphological investigation on plantlets of two accessions cryopreserved under variable preculture conditions.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.80-80
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• 2019

This study describes an efficient and widely applicable droplet-vitrification following cryopreservation for shoot tips of (Fragaria x ananassa DUCH. cvs. 'Derunoka' and 'Jumbo pure berry'. The shoot tips of strawberry were precultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3-0.7M). Precultured explants were treated with loading solution (LS, C4) containing glycerol 17.5% and sucrose 17.5% for 40 min and exposed to dehydration solution (B1) containing 50% of glycerol and 50% of sucrose for 60 min at $25^{\circ}C$, and then transferred onto droplets containing $2.5{\mu}l$ PVS3 on sterilized aluminum foils ($4cm{\times}0.5cm$) prior to direct immersion in liquid nitrogen (LN) for 1 h. The highest regeneration rate (%) was obtained when shoot tips were precultured with treatment-2 (exposing of shoot tips to MS + 0.3M Sucrose for 30 h and then treated with MS+0.5 M sucrose for 16 h) at $25^{\circ}C$ in both the cultivars. The viability of cooled samples, followed by culturing on MS medium for 4 weeks was 77.8% and 60.0% for 'Derunoka' and 'Jumbo pure berry', respectively. This result shows droplet-vitrification would be a promising method for cryobanking strawberry germplasm.

• Korean Journal of Plant Resources
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• v.31 no.6
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• pp.675-683
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• 2018

This study describes an efficient and widely applicable droplet-vitrification following cryopreservation for shoot tips of Chrysanthemum morifolium (Ramat.) cvs. 'Borami' and 'Yes morning'. The shoot tips of Chrysanthemum were precultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3-0.7 M). Precultured explants were treated with loading solution (LS, C6) containing glycerol 20% and sucrose 20% for 30 min and exposed to dehydration solution (B5) containing 40% of glycerol and 40% of sucrose for 60 min at $25^{\circ}C$, and then transferred onto droplets containing $2.5{\mu}l$ PVS3 on sterilized aluminum foils ($4cm{\times}0.5cm$) prior to direct immersion in liquid nitrogen (LN) for 1 h. The highest regeneration rate (%) was obtained when shoot tips were precultured with treatment-2 (exposing of shoot tips to MS + 0.3M sucrose for 30 h and then treated with MS+0.5 M sucrose for 16 h) at $25^{\circ}C$ in both the cultivars. The viability of cooled samples, followed by culturing on $NH_4NO_3$-free MS medium for first 5 days was increased to two-fold (80.7%) regrowth rate over those cultured on normal MS medium or MS medium containing plant growth regulators. This result shows droplet-vitrification would be a promising method for cryobanking chrysanthemum germplasm.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.325-330
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• 2022

In this study, a plant tissue culture system was established for Atractylodes spp., an economically valuable medicinal crop in Korea that has low domestic production and is increasingly imported. In particular, Atractylodes ovata was treated with four types of cytokinins, 6-benzylaminopurine (BA), zeatin, kinetin, and thidiazuron (TDZ), in two different concentrations (0.5 and 1.0 mg/L). Among the four types of cytokinins, the BA treatment was effective for the shoot and root growth of A. ovata. Both the 0.5 mg/L and 1.0 mg/L concentrations of BA showed similar results; however, the 1.0 mg/L concentration of BA was more effective in promoting shoot and root growth. The treatments showed that the TDZ treatment was not effective for the shoot and root growth, except for the number of shoots and the fresh weight (FW) of the root; therefore, it was unsuitable for this species. In this study, we established a mass production system of A. ovata. Our results showed that direct in vitro regeneration may make a significant contribution to improving the cultivation of the medicinal plant A. ovata.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.36-36
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• 2021

Cryopreservation has been broadly used as an efficient method for a long-term conservation for many types of plants especially vegetatively propagated plants. Among several cryopreservation methods, a droplet-vitrification was the most widely applicable and efficient method. Studies have developed protocols for strawberry using droplet-vitrification method and suggested the practical use of the protocol for large number of germplasm with a little modification. In this study, the droplet vitrification method of shoot tip has been tested on 31 accessions provided around the world. Shoot tips were precultured on Murashige and Skoog (MS) liquid medium supplemented with 0.3~0.5M sucrose. Precultured explants were osmoprotected with loading solution, 35% of PVS3 (C4, 17.5% glycerol and 17.5% sucrose) for 40 min and exposed to dehydration solution, PVS3 (B1, 50% glycerol and 50% sucrose) for 60 min. Then, the explants were transferred onto droplets containing 2.5 uL PVS3 on sterilized aluminum foils prior to direct immersion in liquid nitrogen (LN) for 1hr. The cryopreserved shoot tips were rapidly warmed in a water bath at 40C and then unloaded in MS with 0.8M sucrose for 40 min. The shoot tips were cultured in NH₄NO₃-free MS post culture medium for 2 weeks. Subsequently, the explants were moved to the MS medium for 6 weeks and evaluated the regrowth rate. By this droplet-vitrification protocol, twenty-four accessions showed at least 40% regrowth rate. Out of 24 accessions, 'Nonsan1ho' had the highest regeneration rate of 85.8% and 'Jumbo pureberry' had the lowest with 42.1%.

• Korean Journal of Medicinal Crop Science
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• v.8 no.1
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• pp.14-20
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• 2000

This experiment was conducted to investigate the effects of length of storage period under low temperature, $CO_2$ enrichment and addition of plant growth regulators in Murashige and Skoog medium on the plant regeneration of Korean ginseng (Panax ginseng C. A. Meyer). Seeds were treated for 60 and 80 days respectively under $5^{\circ}C$ environment. 2500ppm of $CO_2$ was enriched by ventilation. Three plant growth regulators added to the medium were Indolbutyric acid, Benzyladenin and Gibberellic acid (GA3). The result indicated that : The capacity of differentiation was higher in the aged cotyledons from the seeds treated for 80 days under low temperature condition than in those treated for 60 days. $CO_2$ enrichment had stimulating effects on the growth and development of shoot primordium significantly but less effects on the formation of adventitious buds. From one zygotic embryo hundreds of plantlets were differentiated. $CO_2$ enrichment had effects on the formation of both indirect somatic embryo and direct somatic embryo. Indirect somatic embryo showed little growth and differentiation, being undifferentiated vascular stele and epicotyl. Direct somatic embryos were formed on the epidermis of backside basal part of cotyledon. Those embryos developed to whole plant having latent bud.

• Journal of Plant Biotechnology
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• v.34 no.2
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• pp.153-159
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• 2007

Plant regeneration of Pulsatilla koreana was achieved via adventitious shoot formation indirectly from callus and directly from adventitious root segments. For the callus induction from leaf or petiole explants, combination of 2,4- dichlorophenoxyaceticacid (2,4-D) with $2.22\;{\mu}M$ 6-benzyladenine (BA) was effective. Adventitious shoot induction from callus was enhanced by the combined treatment with $0.1\;{\mu}M$ polyvinylpyrrolidone (PVP) compared to cytokinin treatment alone. Adventitious roots were induced from the petiole segments on 1/2 MS medium with $4.93\;{\mu}M$ IBA. High frequency direct adventitious shoot formation from the segments of adventitious roots was achieved on medium with $4.92\;{\mu}M$ 2-isopentenyladenine (2-ip). Elongated shoots were rooted on half-strength MS medium containing $5.71\;{\mu}M$ indole acetic acid (IAA). Regenerated plantlets with well-developed shoots and roots were successfully transferred to soil. This in vitro propagation protocol might be useful for mass propagation as well as conservation of this plant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.49-54
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• 1999

An experiment was carried out using pots to investigate the effects of Chinese milk vetch on the seedling establishment and growth in rice. Four irrigations with five-day intervals and three different levels of vetch straw were investigated. Significantly higher panicle numbers were obtained in vetch-treated pots. Vetch levels were non-treatment as checks, vetch with top removed, root plus shoot 7.5 ton/ha, and root plus shoot 3.0 ton/ha. The time for complete degradation of vetch straws was reduced from 10 days to 5 days as submerged time was delayed, and was affected by the amount of mulched vetch straws. As the mulched vetch amount increased, the time for a complete degradation was extended from 4 days to 12 days. Grain yield and its components were significantly affected by irrigation time and mulched vetch amount. Effectively controlled, lowered reduction damage from the degrading vetch straw, irrigation date and vetch amount were the most important factors for the improving of seedling establishment in direct-sown rice.

• Journal of Plant Biotechnology
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• v.6 no.3
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• pp.189-192
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• 2004

Adventitious multiple shoots were developed from leaf, petiole and internode explants of Geophila reniformis D. Don. on MS medium supplemented with various concentrations of $N^6$-benzylaminopurine (BAP) or Kinetin (KIN) alone or in combination with indole-3-acetic acid (IAA). Leaf showed maximum organogenetic potential, followed by petiole and internode. Murashige and Skoog (MS) medium supplemented with 22.22 $\mu{M}$ BAP and 4.57 $\mu{M}$ IAA induced maximum shoot buds from leaf explants. Internodal segments showed low potential of direct organogenesis. The regenerated shoots rooted the best in presence of 10.75 - 13.44 $\mu{M}$ $\alpha$-naphthalene acetic acid (NAA) along with 2.22 $\mu{M}$ BAP, and were successfully established in the field with a survival rate of 89.11%.