• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.247-252
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• 2004

In vitro cultures of watermelon were treated with antimitotic agent colchicine to induce ploidy alterations, particularly the induction of tetraploids. Explants cotyledon, embryonic end of seed, transverse sections of epicotyl and hypocotyl were cultured on MS media supplemented with BA ($1{\mu}M$) and colchicine ($0.01\%,\;0.05\%\;and\;0.1\%$). Explants were subcultured on colchicine free media after 4 and 7 days. Colchicine had negative effect on in vitro regeneration but this exhibited explants related response. However, hypocotyl section of seedlings induced maximum callus on $0.01\%$ colchicine. Shoot proliferation was more in cotyledon explants cultured on colchicine ($0.01\%$) for four days. Maximum root induction and root number were recorded in embryonic end explants. Overall, cotyledon and embryonic end explants, and low colchicine concentration ($0.01\%$) was found optimal in watermelon regeneration.

• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.253-258
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• 2004

Plant regeneration depending on explant type was inves-tigated with cotyledon, hypocotyl, and leaf explants of garland chrysanthemum (Chrysanthemum coronarium L.) cultured on MS basal medium supplemented with various concentrations of SAP and NAA combination. Among the three different types of explants, hypocotyl explants grown on MS medium containing $1.0{\mu}M\;NAA,\;1.0{\mu}M\;BA\;and\;6{\mu}M\;AgNO_3$ produced the highest adventitious shoots (4.67 per explant). Hypocotyl explants not only produced more vigorous shoots, which regenerated aster than the cotyledon and leaf explants. An efficient root formation was observed in MS medium containing $3\%$sucrose. The concentration of NAA did not show significant effects on root formation. Results from this experiment suggested that hypocotyl explants were efficient for the regeneration of garland chrysanthemum.

• Plant Resources
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• v.2 no.1
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• pp.10-15
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• 1999

In vitro shoot regeneration from cotyledon and hypocotyl explants derived from germinating mature Impatiens seeds. The induction of organogenetic tissue was also influenced by the cotyledon and hypocotyl. Multiple shoot induction was higher in hypocotyl than in the cotyledon explant with Thidiazuron and a NAA medium.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.133-139
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• 2012

The influences of ethylene inhibitors ($AgNO_3$ and silver thiosulfate) and cytokinins (BAP and TDZ) on shoot regeneration from cotyledon and hypocotyl explants of B. napus cv. Youngsan were investigated. The presence of $50{\mu}M$ Silver thiosulfate (STS) in shoot regeneration medium formed shoots at 60-68% after 3-4 weeks of culture, which was enhanced by 2-fold compared to that of Silver nitrate ($AgNO_3$). Moreover, cotyledon explants were more regenerative than hypocotyls; shoots from cotyledon explants began to occur 4-5 days earlier than that of hypocotyl explants. TDZ at a concentration of $8-10{\mu}M$ was effective for shoot regeneration, compared with BAP. Consequently, the optimal shoot regeneration response was observed in medium supplemented with $50{\mu}M\;STS+8{\mu}M\;TDZ$. In transmission electron microscopy (TEM) analysis, higher density of silver nanoparticles was shown to be accumulated widely inside the cell wall and plasmodesmata of regenerating leaf cultured in medium supplemented with $AgNO_3$. By contrast, in the cell cultured in medium with STS, fine-grained deposits were partly observed in the surroundings of the cell wall.

• Horticultural Science & Technology
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• v.19 no.1
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• pp.17-21
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• 2001

To develop a selection system for regenerating plants from transformed tissues, effects of four antibiotics (kanamycin, hygromycin, carbenicillin, cefotaxime) and herbicide (phosphinotricin) on shoot regeneration from cotyledon and hypocotyl explants of Chinese cabbage (Brassica campestris L. ssp. pekinensis) were studied. For cotyledon, shoot induction was not significantly affected by kanamycin at $1mg{\cdot}L^{-1}$, but the number of shoots formed was significantly reduced at $2mg{\cdot}L^{-1}$, and no shoots were regenerated from any explants at $6mg{\cdot}L^{-1}$ or higher. Hypocotyl explants showed similar result as cotyledon. Kanamycin at $7mg{\cdot}L^{-1}$ may be adequate for selecting Chinese cabbage transformants. Hygromycin at $4mg{\cdot}L^{-1}$ or higher completely inhibited the growth and shoot regeneration of Chinese cabbage explants. Therefore, resistance gene to hygromycin may also be used as a selective marker for Chinese cabbage transformation. Carbenicillin and cefotaxime, the cephalosporin type of antibiotics, had little effect on shoot regeneration of Chinese cabbage explants. Since carbenicillin and cefotaxime have low toxicity to Chinese cabbage, they are suitable for use in tissue culture to eliminate Agrobacterium in transformation experiments after co-cultivation. Shoot regeneration from cotyledon and hypocotyl explants was significantly reduced in presence of $1mg{\cdot}L^{-1}$ phosphinotricin (PPT) and completely inhibited by $2mg{\cdot}L^{-1}$ or higher. PPT, same as antibiotics, may also be used to select transformed cells. Since Chinese cabbage is known to be recalcitrant to in vitro shoot regeneration compared to other Brassica species, even though lower levels of selectable markers result in more transformants but simultaneously allow more untransformed escapes to develop, lower levels of antibiotics and herbicides could be successfully used as a selectable marker to reduce selection pressure.

• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.511-515
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• 2013

Hypocotyls explants of melon seedling were cultured on Murashige and Skoog's (MS) medium supplemented with 1 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5 mg/L benzyl aminopurine (BA) for 6 weeks to produce somatic embryos. In somatic embryos produced through intervening bright yellow friable (BYF) from the explants, somatic embryos with two-cotyledon (26%) and horn-type cotyledon (74%) were observed. The procambial strand of cotyledons was originated from circular procambial tissues of lower hypocotyls. The circular procambial independently divided into two procambial strand at the edge of cotyledonary-node, and then connected to each cotyledon to form somatic embryos with two-cotyledon. When cotyledon was horn-type, the circular procambial strand in lower hypocotyls would continuously remain connected to the cotyledon. However, somatic embryos with two or horn type cotyledon formed an abnormal shoot apex without the tunica-corpus structure or dome shape in the inter-cotyledonary area. These results demonstrated that the variation of cotyledon in somatic embryos was closely related to procambial tissue differentiation and shoot apical formation.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.822-824
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• 2007

The efficient system for plant regeneration from cotyledon and primary feat explants of lettuce was established. Plant regeneration efficiency was shown 91.3% from cotyledon and 85.9% from primary leaf explants of variety 'Jungtongpogi' in KN medium. Plant regeneration efficiency was also estimated with various plant regeneration media in variety' Chungchima', which was lowest plant regeneration efficient showing 35.4% from cotyledon and 30.3% from prima leaf explants in KN medium. Kl medium increased 77.9% and 80.7% of plant regeneration efficiencies from cotyledon and primary leaf explants of variety 'Jungtongpogi' were cultured on KN medium. In case of varie쇼 ‘Chungchima', efficient plant regeneration was shown when primary leaf explants were cultured on SH and KI media.

• Journal of Life Science
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• v.9 no.1
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• pp.29-34
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• 1999

Cotyledon and hypocotyl explants of perilla were cultured on MS medium containing a combined concentration of BA(0.5, 1.0 and 1.5mg/$\ell$) and NAA(0.1, 0.5 and 2.0mg/$\ell$) in order to regenerate the explant and induce the callus. The best regeneration of the explant and induction of the callus were observed in a combined concenteration of 0.5mg/$\ell$ of BA and 0.5mg/$\ell$ NAA both in cotyledon and hypocotyl explants. In cotyledon explants, rooting was achieved upon transferring shoots to MS medium containing 0.5mg/$\ell$ of BA and 0.1mg/$\ell$ of NAA. We also investigated the change of protein and RNA content on developmental stage of callus and plant regeneration of perilla. Protein content was increased but RNA content was decreased as the culture period increases. The banding pattern of polypeptide revealed that both 30KD and 45KD polypeptides were obvious in cotyledon obtained from pre-culture explants, but only 30KD polypeptide was further getting obvious as the culture period increases.

• Plant Biotechnology Reports
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• v.4 no.2
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• pp.101-107
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• 2010

An efficient plant regeneration system has been developed for figleaf gourd (Cucurbita ficifolia Bouch$\'{e}$), which is exclusively used as a rootstock for cucumber. The protocol is based on results obtained from a series of culture experiments involving different parts of the cotyledons and various media. The culture of cotyledon explants was critical for the enhancement of shoot regeneration frequency. The lower parts of the cotyledon excised at the plumule base were found to display a markedly enhanced production of adventitious shoots compared to other cotyledon regions. Culture in silver nitrate-supplemented Murashige and Skoog (MS) medium was not beneficial for shoot regeneration and suppressed root regeneration. Efficient shoot regeneration was obtained on MS medium containing 1.0 $mg\;l^{-1}$ zeatin and 0.1 $mg\;l^{-1}$ indole-3-acetic acid. Regenerated shoots successfully elongated and rooted in medium containing 0.1 $mg\;l^{-1}$ 1-naphthalene-acetic acid after 10-15 days of subculturing. The plantlets were satisfactorily acclimatized in a greenhouse and grew into normal plants without any morphological alterations.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.69-73
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• 2007

A reliable and effective tissue culture system was established for Perilla frutescens (perilla) using different cultivar, explant source, and growth regulator composition in medium. MS medium supplemented with 2.0 mg/L BA and 0.1 mg/L NAA was maximum at shoot induction. Cotyledon explants formed more shoots than hypocotyl explants. The frequency of plant regeneration through organogenesis was higher (22.8%) than that (6.1%) of somatic embryogenesis. Five genotypes of perilla were screened for the feasibility of shoot regeneration, cotyledon explant of 'Manbaek' showed the highest shoot induction at a frequency of 27.3% among the tested cultivars.