• Journal of Plant Biotechnology
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• 제6권3호
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• pp.193-197
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• 2004

In vitro multiplication of Curculigo orchioides was achieved by direct somatic embryogenesis in young leaf segments. Immature leaf segments of about 0.5 cm in length were cultured on MS medium supplemented with different concentrations of BAP (2-10 $\mu{M}$) or Kin (2-10 $\mu{M}$). Optimum response in terms of per cent cultures responding (89%) and the number of embryos per explant (16) were observed on MS medium supplemented with 8 $\mu$M BAP. The emergence of several somatic embryos on the adaxial side of the leaf segments was observed one month after the culture. Germinated somatic embryos were grown up to about 1.5 cm length before transferring to maturation medium. For maturation, the individual embryos were isolated and transferred to MS medium supplemented with BAP (5 $\mu{M}$) and NAA (0.5 $\mu{M}$). The plantlets emerged from the embryos were transferred to soil containing 1 peat: 1 sand with 90% success. The embryos were formed directly on the leaf segments without any callus phase. Direct regeneration of somatic embryos is important for the conservation of this endangered species, as rare somaclonal variants are likely to arise than from indirect regeneration.

• Plant Biotechnology Reports
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• 제3권4호
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• pp.341-345
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• 2009

This study describes culture conditions for a plant regeneration system via a combined pathway of somatic embryogenesis and organogenesis in root explant cultures of the commercial rose cultivar 'Charming'. Root explants formed white calluses at a frequency of 30% after 6 weeks of culture on Schenk and Hildebrandt (SH) medium supplemented with $11mg\;1^{-1}$ 2,4-dichlorophenoxyacetic acid. After 6 weeks of transfer to SH medium without growth regulators, initial white calluses gave rise to globular somatic embryos at a frequency of 2.8%, which were subsequently dedifferentiated to embryonic tissues. Somatic embryos or embryonic tissues initially derived from root explants did not undergo development beyond cotyledonary stage. To produce adventitious shoots, embryonic tissues were sliced and cultured on SH medium with $0.5mg\;1^{-1}$ 6-benzyladenine. After 4 weeks of culture, 28% of embryonic tissue explants formed adventitious shoots. Regenerated shoots were rooted on half strength SH medium with $0.1mg\;1^{-1}$ ${\alpha}-naphthalaneacetic$ acid and subsequently grown to maturity. Root-derived embryonic tissues were proliferated by subculture, while retaining the capacity for shoot production for a few years.

• 식물조직배양학회지
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• 제24권5호
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• pp.285-289
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• 1997

꿩의비름(Sedum-erythrostichum Miq.)의 잎과 줄기의 절편을 몇 가지의 호르몬이 첨가된 MS 배지에 배양하였다. 배양 2주후 2.0 mg/L. 2,4-D와 1.0 mg/L BA를 혼합한 배지에서 잎의 절편으로부터 100%의 캘러스가 형성되었다. 이 캘러스를 2.0 mg/L 2,4-D와 1.0 mg/L BA를 혼합한 배지로 계대배양하였을때 캘러스의 생장이 왕성하였다. 또한 2.0 mg/L NAA와 1.0 mg/L BA를 혼합한 배지로 계대배양한 캘러스로부터 부정아의 분화가 왕성하였다. 생장호르몬이 없는 배지에서 분화된 신초는 1.0 mg/L IAA를 첨가한 배지에서 발근하여 완전한 식물체로 생장하였다.

• Journal of Plant Biology
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• 제27권3호
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• pp.139-147
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• 1984

This in vitro study was employed to clarify the effects of several pollutants i.e. $SO_2$, fluoride, cadmium(Cd), aluminum(Al) and NaCl, on the organogenesis and growth responses of shoot-tip, stem and multiple-buds segments derived from hypocotyl or cotyledon culture of petunia seedlings. ${Na_2}{SO_3}$levels of more than 200$\mu{g}$/ml had significantly reduced organogenesis, growth, and chlorophyll content. The injuries caused by ${Na_2}{SO_3}$, concentration of more than 400$\mu{g}$/ml were alleviated by increasing hydrogenion concentration of medium, indicating some relationship between two factors. Organogenesis was not affected by the fluoride concentration up to 100ppm in the media, but the growth and chlorophyll content were greatly reduced by the fluoride. The effect of Cd depended on the explant sources used for the culture; 1.0ppm was effective for fresh weight increase in shoot tip culture, and 3.0ppm in stem segments culture. Organogenesis and growth were greatly reduced by more than 10.0 Cd treatment. Growth and formation of shoots were better with Na conc. of 0.3% compared to control, but those of roots were inhibited. Na concentration goes over 1.0%, organogenesis and subsequent growth were inhibited, and chlorophyll synthesis was drastically reduced. Chlorophyll content was increased on the medium supplemented with Al 50$\mu{g}$/ml compared to control. However the formation and growth of shoots were greatly inhibited with more than 400$\mu{g}$/ml and roots were not produced at all.

• 한국자원식물학회지
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• 제20권3호
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• pp.251-254
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• 2007

This study was conducted to investigate the optimal plant growth regulator level for the shoot formation of Lycium chinense Mill. In vitro plant propagation was developed for leaf explants of boxthorn. Leaf explants were cultured on MS medium supplemented with cytokinins (BA and 2-iP) alone. Plants were successfully regenerated through in vitro culture by using leaf explants of boxthorn grown in the field. After 4 weeks of culture, 58% of shoot formation had developed from the leaf explants. The shoot formation rate of 'Jangmyeong' was highest followed by 'Myeongan', ;Cheondae', and 'Bullo'. The use of 0.2mg/L BA was critical for enhanced production of shoot formation and resulted in 58% of the culture producing shoot formations. Regenerated plantlets transplanted to pots were developed and successfully acclimatized to greenhouse.

• 한국자원식물학회지
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• 제22권6호
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• pp.522-527
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• 2009

Plants of the genus Taraxacum are well-known as a traditional herbal remedy with a long history, and they have also been extensively used as food, chemicals and cosmetics. In this study, four Taraxacum species distributed in Korea (T. mongolicum, T. officinale, T. mongolicum variation and T. officinale variation) were utilized for an efficient method for direct multiple shooting induction and regeneration, using leaf blade, transition zone, petiole and root as explants in MS media with various hormone concentration and combination. MS medium containing IAA 0.2 mg/L and TDZ 1.0 mg/L showed the highest induction frequency of all the hormone combinations. Besides, the induction of T. mongolicum variation was most effective comparing with the other three species by the average induction frequency of four explants. While the induction effect of leaf blade explant was more obvious than the other three explants. This system exhibited a rapid propagation of shoots from the leaf blade explants and makes it convenient to make use of these Taraxacum species to develop their diverse applications in the future.

• Molecules and Cells
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• 제39권6호
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• pp.484-494
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• 2016

Plant cells have a remarkable ability to induce pluripotent cell masses and regenerate whole plant organs under the appropriate culture conditions. Although the in vitro regeneration system is widely applied to manipulate agronomic traits, an understanding of the molecular mechanisms underlying callus formation is starting to emerge. Here, we performed genome-wide transcriptome profiling of wild-type leaves and leaf explant-derived calli for comparison and identified 10,405 differentially expressed genes (> two-fold change). In addition to the well-defined signaling pathways involved in callus formation, we uncovered additional biological processes that may contribute to robust cellular dedifferentiation. Particular emphasis is placed on molecular components involved in leaf development, circadian clock, stress and hormone signaling, carbohydrate metabolism, and chromatin organization. Genetic and pharmacological analyses further supported that homeostasis of clock activity and stress signaling is crucial for proper callus induction. In addition, gibberellic acid (GA) and brassinosteroid (BR) signaling also participates in intricate cellular reprogramming. Collectively, our findings indicate that multiple signaling pathways are intertwined to allow reversible transition of cellular differentiation and dedifferentiation.

• Journal of Applied Biological Chemistry
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• 제59권2호
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• pp.149-154
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• 2016

An endophytic bacterial strain was isolated from kimchi, a Korean traditional fermented Brassica campestris and identified as Bacillus subtilis MJMP2 based on the 16S rRNA sequence. This strain showed strong antagonistic activity against Xanthomonas oryzae pv. oryzae (Xoo) KACC10331, the pathogen of bacterial rice blight disease, as well as activity against some other rice phytopathogenic fungi. The active compound was purified through size-exclusion chromatography and preparative High-performance liquid chromatography. The molecular weight was determined as m/z 1043 by mass spectroscopy, which is identical to that of iturin A. Furthermore, a crude extract from the culture supernatant of Bacillus subtilis MJMP2 showed inhibitory activity against rice blight disease in both a rice leaf explant assay and a pot assay. The crude extract also enhanced the length of roots of Arabidopsis thaliana. These results suggest that the strain Bacillus subtilis MJMP2 could be used as a biological agent to control rice blight disease.

• Journal of Plant Biotechnology
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• 제5권2호
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• pp.131-135
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• 2003

Callus and cell suspension cultures of Eurycoma longifolia Jack were initiated from leaves of different trees. The leaf explant of tree Eu9 produced the most calli and also induced high cell biomass in the cell suspension culture. Optimum production of cell biomass could be initiated in proliferating culture medium with a pH of 5.75 prior to autoclaving. The effects of macronutrient inorganic salts of Murashige and Skoog (MS) liquid medium supplemented with X on production of cell biomass of Eurycoma longifolia were also investigated. The highest cell biomass was produced in MS medium containing macronutrients of $21\;mM\;NH_4NO_3,\;12.25\;mM\;KNO_3,\;3.00\;mM\;CaCl_2.2H_2O,\;0.575\;mM\;MgSO_4.7H_2O$, and $1.83\;mM\;KH_2PO_4$. A new medium labeled as TAM was formulated for the production of Eurycoma longifolia cell biomass in the cell suspension culture.

• Journal of Plant Biotechnology
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• 제5권2호
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• pp.107-113
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• 2003

The effect of sodium sulphate on shoot induction and multiple shoot formation from nodal explants of Vitex negundo L. was tested on Murashige and Skoog's (MS) medium fortified with different auxins, cytokinins and sucrose. Highest percentage $(97.78\%)$ of explants for shoot induction and multiple shoot (20.68/explant) production were observed in the combination treatment of $N^6-Benzyl$ adenine (BA) $(17.80\;{\mu}M/L)$, ${\alpha}-Naphthalene$ acetic acid (NAA) $(2.15\;{\mu}M/L)$ and $5\%$ sucrose supplemented with 100 mg/L sodium sulphate. In vitro raised shoots were rooted on the half-strength MS medium fortified with different concentrations of NAA, Indole-3-acetic acid (IAA), and Indole-3-butyric acid (IBA) alone and in combinations. Among the treatments, $4.90\;{\mu}M/L$ of IBA was found most effective $(95.56\%)$ in inducing roots. The rooted plantlets were shifted to glasshouse for acclimatization and later transferred to the field with cent percent survival. Furthermore, in vitro flowering was observed in the shoots cultured on MS medium supplemented with BA $(8.90\;{mu}M/L)$ and NAA $(1.61\;{\mu}M/L)$.