• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.406-413
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• 2009

The enzyme invertase contributes to sugar unloading, pathogen defense, differentiation and development in plants. We cloned the complete cDNA of a soluble acid invertase from pea seedlings (Pisum sativum) via RT-PCR and the rapid amplification of the cDNA end (RACE) technique. The full-length cDNA of the soluble pea invertase comprised 2237 bp and contained a complete open reading frame encoding 647 amino acids. The deduced amino acid sequence showed high homology to soluble acid invertases from various plants. Northern blot analysis demonstrated the soluble acid invertase gene of P. sativum was strongly expressed in sink organs such as shoot tips and root tips, and induced by abscisic acid, gibberellic acid and jasmonic acid in shoots. Especially, gibberellic acid enhanced the gene expression of the soluble acid invertase in a time-dependent manner. This study presents that the gene expression patterns of a soluble acid invertase from pea are strongly consistent with the suggestion that individual invertase gene product has different functions in the growing plant.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.87-91
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• 1997

In vitro grown microtubers of potato (cv Jaju) were used for introduction of herbicide resistance gene using bombardment with DNA-coated particles. The apical shoot-tip area of newly sprouted microtubers were intensively bombarded. After bombardment, microtubers were germinated and transplanted in a greenhouse. Northern blot analysis indicated that bar gene was expressed in two plantlets. After 5 weeks of growing, commercial herbicide Basta was sprayed to screen the resistant plants. All untransformed potato plants died after 7 days while two transgenic plants survived.

• Journal of Plant Biotechnology
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• v.35 no.2
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• pp.163-167
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• 2008

Adventitious buds appeared within 2 weeks on the base of the petiole explants and increased for two months. A maximum of regeneration (15.6%) was obtained on the medium containing $1.5\;{\mu}M$ TDZ in combination with $1\;{\mu}M$ IBA. To know which explants are the best for the induction of regeneration, three explants such as leaf, petiole and leaf-petiole were used. Among the explant types, the leaf-petiole explant was significantly more effective than leaf and petiole for promoting adventitious shoots, with leaf-petiole inducing at the highest regeneration frequency (33.7%). The regeneration frequency of adventitious shoots in the leaf-petiole explants was significantly affected by leaf size and the position of explants. The leaf-petiole smaller than 5 mm leaf in width was induced at the highest regeneration frequency (68.9%). The smaller leaf sizes, the greater regeneration frequency. Also when the leaves are nearer to the shoot tip, the regeneration frequency is higher. When the rooted micro-shoots were transferred to the soil after growing for 6 weeks in the media, the survival rate was 90%.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.88-94
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• 2005

Plant tissue culture studies have been done for the preservation of medicinal plant resources and efficient production of pharmaceutically important secondary metabolites. Micropropagation methods for Cephaelis ipecacuanha have been established and these methods enabled much more efficient propagation of the plants than the conventional methods using seedling or layering. The C. ipecacuanha plants derived from tissue culture grew uniformly in the field and they showed higher alkaloid contents compared to the plants grown from seedlings. Hairy root cultures of C. ipecacuanha and Panax ginseng have been established by infection with Agrobacterium rhizogenes, and the production of important pharmaceuticals by these cultures have been successfully demonstrated. In the case of C. ipecacuanha, the highest alkaloid yields from the hairy roots cultured for 8 weeks were 2.75-fold cephaeline (5.5 mg) and one third emetine (0.7 mg) compared with those from the roots of one-year old plant propagated through shoot-tip culture and cultivated in a greenhouse (2.0 mg cephaeline and 2.0 mg emetine). In the case of P. ginseng, ginsenoside contents in the hairy roots optimally cultured for 4 weeks were much higher than those in the roots of 4-year old field-grown plant. Thus our medicinal plant tissue cultures demonstrate desirable properties. However, they are always exposed to danger of microbial contamination or unexpected trouble of culture facilities. Cryopreservation of plant tissue cultures is a reliable method for long-term preservation. Cryopreservation studies on these cultures are also presented.

• BMB Reports
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• v.43 no.12
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• pp.813-817
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• 2010

Plants undergo cell division throughout their life in order to maintain their growth. It is well known that root and shoot tip of plants possess meristems, which contain quiescent cells. Fluridone (1-methyl-3-phenyl-5-(3-trifluromethyl (phenyl))-4-(1H)-pyridinone) is an established inhibitor of both ABA and carotenoid biosynthesis. However, the other functions of fluridone remain undiscovered. In this report, we provide experimental evidence that fluridone plays a role in the division of the quiescent centre of the Arabidopsis root meristem. This study examined the effects of exogenous fluridone and ABA on the development of the stem cell niche in Arabidopsis root. We show that fluridone promoted the division of stem cells in the quiescent centre, whereas exogenous ABA suppressed quiescent centre division. Furthermore, we established a novel regulatory function for fluridone by demonstrating that it plays an important role in postembryonic development.

• Journal of Sericultural and Entomological Science
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• v.36 no.1
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• pp.1-7
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• 1994

Four tetraploid mulberry lines, Sawonppon No.11, No.13 and No.14, were induced by the colchicine treatment on the shoot tips of seedlings originated from the cross between Yongchonppong and Kaeryanppong. The major characteristics of the tetraploid lines were as follows: Green tip sprouting stage was similar to Kaeryanppong, a medium budding variety. Leaves were medium- to large-sized cordate type. Leaf surface was rougher and stronger than that of the diploid parents. Leaf thickness, leaf area weight and leaf water content were higher than those of the diploid parents. Average branch length was shorter than that of the diploid parents. Internode length and number of lateral branches were similar to the average values of the two parents. Death atop rate of branch was 1.6%~2.5% indicating strong cold-hardiness of the tetraploid lines. Therefore, these lines could be used as sources of cold-hardiness in developing triploid lines.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.401-408
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• 2017

Herein, we report the meristem-tip culture from dormant buds of grape 'Kyoho' single-infected with Grapevine fleck virus (GFkV), which is phloem-limited and transmitted by graft inoculation. We produced GFkV-free shoots without thermo- or chemotherapy using meristem-tip explants approximately 0.3 mm (73 explants) and 0.8 mm long (five explants) including shoot apical meristem, 2-5 leaf primordia, and 1-4 uncommitted primordia from dormant buds of the infected woody cuttings (stored at $4^{\circ}C$). Explants were cultured on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 3.0 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-butyric acid (IBA). After 16 weeks of culture, shoot (10-mm long) regeneration frequency achieved from 0.3-mm explants was 4.1% and that obtained from 0.8-mm explants was 40.0%. Virus-free efficiency (expressed as the percentage of RT-PCR negative shoots regenerated) from 0.3- and 0.8-mm explants was 100% and 50%, respectively. Following in vitro multiplication, RT-PCR assays revealed identical results to assays of the first regenerated shoots. Our new methodological approach could be applied for eliminating other viruses in grapevines, as well as for producing virus-free plants in many other deciduous tree species, including fruit trees.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.121-126
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• 1999

Calli were induced from the petiole explants of Pimpinella brachycarpa on MS medium supplemented with 0.5 mg/L 2,4-D and 0.1 mg/L BA after four weeks of culture. Compact clusters of small and dense cells among these calli were selected and suspension-cultured as the source of embryogenic calli. When transferred to MS medium with 0.1 mg/L NAA, the suspension-cultured cells grew to embryogenic callus. Somatic embryos derived from these embryogenic calli developed into plantlets. The cDNA library was constructed in the embryogenic callus and in order to screen the cDNA library, these cDNAs were plated at a density 1.5 $\times$ 10^5 plaques per 15 cm petridish. Among 19 clones showing preferential hybridization with petiole HD-Zip gene, five clones were obtained after second screening. Four clones among them, were highly homologous to P. brachycarpa shoot-tip Phz4 gene, but one clone, Phc5 was about 1.5 kb which has an extra 163 bp to 5' upstream of Phz4. The Phc5 was 1,531 bp containing poly A tails of 18 bases. ATG start codon for Phc5, was located at position 284 with an open reading frame of 906 by which encodes a polypeptide of 302 amino acids. The Phc5 protein revealed that the polypeptides between 135 and 195 contain a homeodomain as the `leucine zipper' motif.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.4
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• pp.344-349
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• 1981

This study was conducted to define the effect of 2.4-D, NAA, Benzyladenine, and basic mediums on the callus induction and the organ differentiation from the meristem tips and the stem and leaf segments of the potato. Benzyladenine promoted the induction and growth of shoot from the meristem tip of potato but inhibited initiation of roots and induction of callus. At higher concentration of NAA than 0.5 ppm and of 2.4-D than 1.0 ppm the shoots were not initiated but the callus was induced from the meristem. The callus growth was significantly promoted on the medium containing NAA than 2.4-0. The initiation and growth of the shoots from the potato meristem was significantly increased in the medium containing 2.4-D and BA, or NAA and BA, compared with those containing BA, NAA or 2.4-D alone. The callus was more easily induced from the stem segments than the leaf segments of potato. And the 2.4-D was more effective for the induction and growth of the callus than the NAA. MS medium diluted its concentration to 1/2 was more suitable for the initiation and growth of the shoots from the potato meristem than the MS standard medium. For the initiation and growth of the shoots from the potato meristem, the most desirable medium was the diluted MS medium containing 1.0 ppm BA and 0.1 ppm NAA or 0.1 ppm 2.4-D.

• ALGAE
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• v.25 no.4
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• pp.187-195
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• 2010

The genus Rosenvingea is well known in the tropics. Four species have been reported from Pacific Mexico: R. floridana, R. antillarum, R. intricata and R. sanctae-crucis. We collected a plant (Boca del Cielo, Chiapas) that we identified as Rosenvingea orientalis, a species not previously reported from Pacific Mexico. We were able to characterize the life cycle of this species for the first time in laboratory culture. It reproduced exclusively by plurilocular sporangia (plurangia). The mature plants were up to 6 cm long with cylindrical to compressed fronds (to 2 mm wide) with dichotomous branches in the upper half of the thallus. The medulla was hollow with 2-3 layers of large inflated colourless cells at the periphery. The cortex was comprised of 1 layer of small cells, each with a single chloroplast and pyrenoid. Linear plurangial sori with phaeophycean hairs formed along the mature fronds. Zoospore germlings developed into prostrate filamentous systems, each with a single phaeophycean hair that gave rise to a single erect shoot with multiple hairs arising near the tip. Molecular phylogeny using the psaA gene placed this isolate within the Scytosiphonaceae. It does not confirm the exact identification of R. orientalis, although its placement close to other Rosenvingea sequences was confirmed and morphological evidence supports its placement in R. orientalis. Our culture investigations indicated that it has an asexual life cycle. Further collections are needed to resolve the full generic and specific relationships of Rosenvingea and related taxa, and their reproductive patterns.