• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.347-351
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• 1994

To measure the time required for ginseng explants to become determined to form flower buds, we cultured zygotic embryos, seedlings, and cotyledonary nodes on MS medium supplemented with BA and GA$_3$of 5 ${\mu}$M each (flower inducing medium, FIM) for various periods and transferred to the basal medium. The explants required a minimum of 10 days on FIM to be determined. Histological observations revealed that the axillary meristem to be fated to develop into flower bud remained in a state of shoot meristem during the first 10 days of culture and differentiated into flower bud after 15 days of culture. We suggest that the in-vitro flowering system described in this study is useful in investigating (a) regulatory element(s) to cause the phase change from the vegetative to reproductive state by comparing predetermined explants with determined ones at the molecular level.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.259-274
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• 2017

Platycodon grandiflorum (Bell flower) is an important plant that has traditionally been used as herbal medicine for the treatment of cough, phlegm, sore throats, lung abscesses, chest pains, dysuria, and dysentery. The present study was initiated to investigate the feasibility of inducing shoot and root organogenesis in cultured explants of P. grandiflorum in a range of culture media and through use of various plant growth regulators (PGRs). The plantlets (Stem containing one node) were isolated and cultured on different concentrations of Murashige and Skoog (MS) medium supplemented with PGRs. We found that proliferation and elongation of shoots and roots could be achieved on 1/4 MS for P. grandiflorum with wild and green petals and on 1/8 MS for P. grandiflorum with double petals. The highest levels of development and elongation of adventitious shoots and roots were observed when petal explants were cultured on 1/4 MS (pH 3.8) supplemented with 5% sucrose. Increasing the agar concentration reduced shoot growth and rooting potential; nevertheless, the highest number of shoots and roots was observed on 0.6% agar. In the case of growth regulators, 1/4 MS supplemented with $1mg\;L^{-1}$ 6-benzylaminopurine (BA) was found to be best for shooting, although higher concentrations of BA tended to reduce shoot and root elongation. The highest number of shoots was achieved on $0.5mg{\cdot}L^{-1}$ thidiazuron (TDZ) from double petal explants grown on 1/8 MS. However, root and shoot elongation were found to decrease when TDZ concentrations were increased. Low concentrations of kinetin, naphthalene acetic acid, indole acetic acid, and 3-indole butyric acid induced shoot and root proliferation and elongation. Taken together, our study showed that low concentrations of PGRs induced the greatest root formation and elongation, showing that the optimal concentration of PGRs for shoot proliferation was species-dependent.

• Korean Journal of Medicinal Crop Science
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• v.2 no.1
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• pp.60-66
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• 1994

This study was conducted to determine the optimum conditions of inducing callus, proliferating callus, forming somatic embryos, and regenerating plantlets via somatic embryogenesis, for the purpose of producing artificial seeds and substantially developing plant factory technologies that can be employed to all seasons production of Bupleurum plants. Callus was efficiently induced from leaf tissues at three leaf stage in the MS medium supplemented with 2, 4-D 2mg /1 and thidiazuron(TDZ) 0.lmg /1. Callus induction from leaf tissues at maturity was mostly effective in the mixture of 2,4- D 2mg /1 and TDZ 1.0mg /1 while that from flower bud tissues was fairly good in the MS medium containing 2,4-D 1 or 2mg /1.Callus was formed in 15 to 20 days after culture initiation in the MS media supplemented with 2, 4- D 1-2mg /1 and TDZ 0.l-1.0mg /1. Such hormones as kinetin 3mg /1, GA 1mg /1, and the mixture of GA 1mg /1 and TDZ 1mg /1 effected markedly to proliferate the callus cells.The optimum temperature and light intensity for callus culture were found to be $25^{\circ}C$ and 3000 Lux, respectively. Direct plant regeneration from cultured callus was fairly made on hormone-free MS or half-strength MS medium. Somatic embryogenesis was most frequently observed in hormone-free media:60 somatic embryos per 20ml in MS medium and 28 somatic embryos per 20ml in half -strength MS medium. There were three stages-globular, heart, and torpedo-in development of somatic embryos, among which globular stage was more frequently observed in MS medium rather than in half-strength MS medium. Somatic embryos induced from suspension culture fairly differentiated a number of shoots and roots on hormone-free and half-strength MS solid medium.