• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1141-1147
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• 2006

This study was carried out to establish a reproducible culture system for callus formation and adventitious shoot development from young stem segments of Vigna radinta, and histological work for orgin of callus tissue and adventitious shoot. Induction of callus from young stem explants of Vigna radiata was very effective on MS inorganic salts supplemented with 0.5 mg/L 2,4-D and 1.0 mg/L kinetin. For the adventitious shoot regeneration from the callus tissues, the hormone combination of 0.75 mg/L NAA, 1.5 mg/L kinetin and MS salts resulted in about 21% efficiency. Histological examination showed that callus tissues originated from out-growths by callus cambium rings with do novo meristematic activities, which were localized at the outside of the vascular cambium. Adventitious shoots were developed from shoot apical meristem originated from the surface of callus masses. The shoot apical meristem produced leaf primordium, which then became leaf.

• Korean Journal of Plant Tissue Culture
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• v.21 no.5
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• pp.303-308
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• 1994

Shoot apical meristem dome explants from cassava plants (Ghanaian local variety) produced somatic embryos at a frequency of 32% when cultured on MS medium supplemented with 2 mg/L 2,4-D. Somatic embryo segments formed secondary embryos at frequencies of up to 93% when cultured on medium containing 1 mg/L 2,4-D for 2 to 3 weeks. Since the somatic embryos were not capable of converting into plantlets, adventitious shoot were induced from the sliced embryo segments by culturing them on medium containing 0.1 to 5 mg/L BA. After 8 weeks of culture, numerous shoots formed on the segments at frequencies up to 100%. The shoots were rooted and successfully transplanted to potting soil.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.1051-1056
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• 2010

This study was carried out to determine suitable in vitro culture conditions of new ever-bearing strawberry ($Fragaria$ $ananassa$ Duch.), 'Goha'. Four-week old plantlets which were derived from the meristem culture were used in this study. Three different culture media including MS, Gamborg B5 and White medium were used for the plant culture and the medium concentrations were at the 5 levels of $1/3{\times}$, $1/2{\times}$, $1{\times}$, $2{\times}$ and $3{\times}$. Sucrose content ranged at four levels of 1, 3, 5 and 8% (w/v). Crown diameter on the MS medium was thicker (2.1 mm) than in other media. Fresh weight on the MS medium was 482 mg, which was heavier than 88 mg or 260 mg of Gamborg B5 or White medium, respectively. Particularly, 1/2MS medium was found to have higher growth rate than these in other treatments (fresh weight, dry weight and D/F rate). Shoot length in the treatment of 1% sucrose concentration was 3.6 cm which was the longest. Shoot length was in inverse proportion to the increasing concentration of sucrose. Fresh weight was increased up to 3% sucrose concentration, but decreased above 5% sucrose concentration. From the results, we found that the best condition for in vitro culture of new ever-bearing strawberry 'Goha' was 1/2MS medium supplemented with 1% sucrose concentration.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.233-236
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• 2006

This study was conducted to investigate somatic embryogenesis capacity using callus derived from bud meristems in sweetpotato. Shoot apical meristem explants $(height:150{\mu}m;base:\;350{\mu}m)$were cultured on MS medium supplemented with 1 mg/L 2/4-D. Embryogenic callus were observed in five cultivars when their shoot apices were cultured on MS medium supplements with 1 mg/L 2,4-D. After 6 weeks of culture, greater than 80% of the survived explants produced embryogenic calli and the calli gave rise to somatic embryos at frequencies of 72% (Yulmi), 60% (Shinhwangmi), 78% (Geonmi), 70% (KoKei 14), 40% (Sinjami). The regenerated plants developed into whole plantlets after they were transferred onto the fresh hormon-free MS medium of 74% (Yulmi), 82% (Shinhwangmi), 86% (Geonmi), 74% (Kokei 14), 41% (Sinjami) respectively.

• Journal of Plant Biology
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• v.37 no.1
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• pp.17-25
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• 1994

Two potato (Solanum tuberosum L.) cultivars were transformed by Agrobacterium tumefaciens harboring cauliflower mosaic virus (CaMV) 35S promoter and $\beta$-glucuronidase (GUS) gene. Expression patterns of the CaMV 35S promoter according to tissue types and developmental stages, and genetic stability of GUS gene were investigated in the clonal progenies of transgenic potatoes. Kanamycin-resistant shoot emerged from tuber disc after 4 weeks of culture, and root was induced 6 weeks after culture on the selection medium. Shooting frequency of cvs. Superior and Dejima were 43% and 27%, respectively. Mature transformants and their clonal progenies showed no phenotypical abnormality. GUS activity was expressed primarily at parenchymatous cells of phloem tissue around the vascular cambium in the stem and root, and higher activity was found at the apical meristem of shoot, root and adventious shoot bud. GUS activity was higher at tubers of young explants than at stored tubers. These facts indicate that expression level of the CaMV 35S promoter differed according to tissue types and developmental stages of the organs. The GUS gene was stably inherited to each clonal progeny and normally expressed.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.59-64
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• 1980

These experiments were carried out to define the effects of 2.4-D, NAA and Benzyladenine on the differentiation and growth of the organs and the induction of callus from the potato meristem. The results were summarized as follows ; 1. The differentiation and growth of the shoots from the potato meristem was promoted in increased concentration of Benzyladenine but the callus was not induced on the M.S. medium containing Benzyladenine. 2. On the M.S. medium containing NAA 0.5 mg/l or higher concentration of NAA, the shoots were not initiated but the callus were induced from potato meristem. The growth of callus was promoted in increased concentration of NAA. 3. The roots were initiated from 50% of potato meristems planted on the M.S. medium containing more than 0.1 mg/l of NAA but the roots were pot initiated on the medium containing 2.4-D. 4. The shoot growth was significantly increased by increasing of 2.4-D concentration up to 0.1 mg/l, but the shoots were not initiated on the medium containing 2.4-D more than 1.0 mg/l. 5. For the induction and growth of the callus from potato meristem, NAA was more effective than 2.4-D and the most effective medium was M.S. medium supplemented with 2.0 mg/l of NAA. 6. The M.S. mediums supplemented with BA 2.0 mg/l and NAA 0.1 mg/l or BA 1.0 mg/l and 2.4-D 0.1 mg/l showed good results for entire plant regeneration from potato meristem.

• Journal of Plant Biotechnology
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• v.33 no.4
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• pp.263-270
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• 2006

Pongamia pinnata Pierre is a tree legume, having potential in production of raw material for biodiesel. A protocol for in wk propagation of this plant was standardized using seedling explants. Growth regulators (GR) including gibberellic acid $(GA_3),\;N^6-benzylaminopurine(BA)$, thidiazuron (TDZ), and Adenine sulphate (Ads) were tested for optimum germination of seeds. Removal of seed coat prior to germination, controlled fungal growth partially but enhanced bacterial growth. Antibiotic cefotaxime was ineffective in controlling bacterial contamination. Seedling derived nodal explants and cotyledon nodes with attached cotyledons were excised and cultured for induction of shoots. Optimum sprouting and multiplication of shoot buds were obtained in MS medium supplemented with $8.88{\mu}M$ BA. These buds differentiated and rooted on medium devoid of GR. Optimum growth of Pongamia seedling was obtained in cotton plugged culture vessels. Reculturing of the cotyledon node explants produced more shoots from the same site. This process of removing shoots and reculturing of cotyledon node was followed for eight passages yielding 4 to 8 shoots in each cycle. The shoots (75%) rooted on half strength MS basal medium supplemented with 0.22% charcoal. All plants survived on transfer to soil. This is the first report on in vitro regeneration of Pongamia pinnata. This report demonstrates the possibility of coupling more than one parameter in single experiment to hasten the process of standardization. The process of cycling the nodal explant repeatedly for production of large number of shoots from single meristem may find application in genetic transformation experiments wherein meristems are used for transformation.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.370-378
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• 2010

This review describes the stratagies of development of virus-resistant Alstroemeria plants using the genetic modification system. Despite of increasing of its importance in cut flower market, improvements of some horticultuirally important traits such as fragrance, long vase-life, virus resistance and tolerance against abiotic stresses are lack of the breeding program in Alstroemeria. Of these traits, virus-resistance is quite difficult to develop in Alstroemeria plants due to the limitations of genetic variation in the existed germplasm. To extend the genetic variation, plant biotechnological techniques such as genetic transformation and tissue culture should be combined to develop virus-resistant line in Alstroemeria. In this review, several strategies for the generation of virus-resistance by using natural resistance genes, pathogen-derived genes and other sources including pathogen-derived proteins, virus-specific antibodies and ribosome-inactivating proteins are presented. Also, brief histories of breeding, tissue culture, and transformation system in Alstroemeria plants are described to inderstand of the application of transgenic approach for the development of virus-resistance in Alstroemeria species.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.100-104
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• 2014

This study was conducted to determine the optimal MS medium strength to improve sprouting rate of apical meristem of strawberry 'Seolhyang' in vitro. Strawberry apical meristems at size (0.2 mm to 0.3 mm) with leaf primordials were cultured on the MS media with four strength levels, ($1/4{\times}$, $1/3{\times}$, $1/2{\times}$, and $1{\times}$) and the sprouting rate and growth characteristics were evaluated after eight weeks after cultivation. Shoot rate of 'Daewang' apical meristems was 93.6%whereas 'Seolhyang' apical meristems were sprouted with 31.6% on $1{\times}$ MS medium strength. Different sprouting rates were observed in 'Seolhyang' apical meristem with 31.6% in $1{\times}$ medium, 75.0% in $1/2{\times}$ medium, and 94.4% in $1/3{\times}$ medium. The sprouting rate was improved with the decrease of medium strength, but the shoot rate in $1/4{\times}$ medium decreased up to 54.5%. Shoot length was 0.9 cm in $1{\times}$ medium, 1.2 cm in $1/2{\times}$ medium, 1.6 cm in $1/3{\times}$ medium, and 1.9 cm in $1/4{\times}$ medium. Shoot length was longer as medium strength decreased and numbers of leaves and roots were not significant differences among the medium strengths. As a result, sprouting rate was highest and plant growth was best in $1/3{\times}$ MS medium compared to the others.

• Journal of Plant Biotechnology
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• v.40 no.1
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• pp.55-58
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• 2013

Immature embryos of Glycine max L. was cultured on Murashige and Skoog's (MS) medium supplemented with 1 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D). After 6 to 8 weeks of culture, immature embryos produced somatic embryos. Of somatic embryos, two cotyledonary embryo (14%), one cotyledonary embryo (37%), fused cotyledonary embryo (43%), and stunted globular embryos (6%) were observed. The procambial strand of cotyledons originated from circular procambial tissues of lower hypocotyl. The circular procambial tissues were independently divided into one or two procambial strand at the edge of cotyledonary-node, and then connected to each cotyledon to form somatic embryos with one or two cotyledons. When cotyledon was a fused type, the circular procambial strand in lower hypocotyl was continuously connected to the cotyledon. Also, somatic embryos with two cotyledons developed a functional shoot apex with the tunica-corpus structure. In contrast, somatic embryos with one or fused cotyledon formed an abnormal shoot apex without the tunica-corpus structure or with non-dome shape in the inter-cotyledonary area. These results indicated that the variation of cotyledon in somatic embryos is closely related to procambial differentiation and shoot apical meristem development.