• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.15-21
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• 2005

The expression patterns of cyclin genes, which play a crucial role on cell cycle control, were analyzed with rice calli and leaf blades from seedlings. When callus was transferred from media containing the combinations of 2,4-D and kinetin under the dark conditions to medium supplemented with cytokinin-only on 7 days after the cultures, the expression levels of A-, B- and C-type cyclins from callus were increased significantly. Despite the fact that cyclin genes were well expressed on leaf blades rather than other organs in rice seedlings, rice leaf blades grown on the medium containing various combinations and concentrations of cytokinin for 24 hours had no major effect on the expression patterns of cyclins except zeatin. The relation between cytokinin regulation and the expression of cyclins of rice is discussed.

• Current Research on Agriculture and Life Sciences
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• v.16
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• pp.31-36
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• 1998

In order to investigate the effect of cytokinins on the cotyledonary variability of somatic embryos in Heracleum moellendorffii Hance., somatic embryos were induced from the immature zygotic embryo on MS medium containing 1.0mg/l 2, 4-D, and then transferred to 2,4-D-free and cytokinin-added medium for somatic embryogenesis after 4weeks culture. Polycotyledonary embryos were formed most abundantly(84.9%) on the 0.2mg/l BA medium as compared with the 0.2mg/l 2ip(42.6%) and kinetin(32.9%) media, and it was proportional to BA concentrations(0.01~0.1mg/l). The rate of polycotyledonary embryo formation increased proportional to the period of BA treatment and also increased more at the globular stage than at the heart, torpedo-shaped and cotyledonary stages.

• FLOWER RESEARCH JOURNAL
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• v.18 no.1
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• pp.23-28
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• 2010

This study was conducted to determine the optimal rooting media composition and plant growth regulators for the mass production of new three cultivars in Dendrobium. Rooting medium experiments showed that shooting rate of 'Fizz' was the highest in perlite (Per) and vermiculite (V) mixture (1 : 1, v/v). Rooting rate of 'Prince' was 10% in the same treatment 60 days after cutting, while those of 'Candy' and 'Fizz' showed no shooting. With various kinds of auxin and different levels of concentrations, shooting rate in the other cultivars except 'Candy' increased highly at 60 days after cutting. Whereas, there were no differences between control and treatment except that of 'Fizz' with 200 ppm of IBA treatments showing 86.7%. Rates of cutting with leaves of 'Candy' and 'Fizz' were fairly high with 200 ppm of IBA compared to the control. Rate of rooting of 'Prince' was twice with 200 ppm of IBA or 50 ppm of NAA compared to the control. With various kinds of cytokinin and different concentrations, shooting rate of 'Candy' was 20% with 50 ppm of BA at 60 days after cutting; however, that of 'Fizz' increased in all treatments in 30 days after cutting and reached 100% with 200 ppm of BA compared to the control which was 77% at 60 days after cutting. Kinetin treatment had little effect on shooting rate compared to control at all concentrations. Treatment with 200 ppm of BA had clear effect on the rate of cutting with leaves of 'Fizz' and 'Prince', which was similar to shooting rate. However, the same treatment of BA had no effect on the rooting rate in all cultivars.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.1
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• pp.1-6
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• 1993

This experiment was conducted to select acid tolerant cells from red clover suspension culture and obtained following results. The most effective condition of plant growth regulators for suspension culture of red clover cells was 2 mg/l 2,4-D as auxin source plus 0.5 mg/l BAP as cytokinin source. Among serveral basal media, PC medium brought the best result. The most suitable EMS concentration for the mutated cells tolerant to acid was 1 % with fours treatment and average 27 colonies/plate were selected. The frequency of the occurence of mutants tolerant to acid in 1 % EMS with four hours treatment was 8.9 $\times$ 10$^{-5}$ which was 100 times larger than that of control. The total colonies selected initially were 176 but the survived colonies after two subcultures with 4 weeks interval in a selection medium were 44.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.3
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• pp.124-128
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• 1989

This experiment was conducted to determine factors affecting callus induction of Vernal alfalfa. Growth regulators, basal medium, medium pH, explant age, and agar concentration for callus induction were investigated. The results obtained were as follows: For the callus induction, 2-5 mg/l 2,4-D alone was found to be most effective on callus induction. Cytokinins did not have positive effect on the callus induction, and even the more cytokinin added induced the less callus. Callus yield was much higher in B5 or SH medium than in any other media. The calli induced in PC and MS media were more friable than those induced in other media. The medium pH of 5.8 gave the best response of callus induction. At higher than pH 7.0, callus induction was inhibited severely. The effective seedling age for callus induction was around 9 days. In agar concentration, 0.5 % (W/V) was suitable for callus induction and it was severely depressed at above 1 %. Callus induction was not influenced by day length or illumination. Calli cultured under 1618 hour lightldark cycle became more compact and green than those cultured under the dark.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.198-208
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• 1989

Cell suspension cultures for Salix koreensis was well established at the supplements of 2, 4-D with cytokinin particulary the combination of 1.0 mg/l 2, 4-D with 0.1 mg/l of zeatin. These combined rates of phytohormones are also effective to callus induction from S, koreensis leaf and its multiplication. Cultured media exhibited the great inhibitory effect on the germination of rice, barnyard grass and lettuce seeds, indicating the presence of biologically active substances in media. Several phenolic compounds such as pyrogallol, sinapic acid, cinnamic acid, tannic + gallic and p-chlorobenzoic acid were detected in the cell suspension culture. The inhibitory effect exhibited by cultured media may be partly attributed to these phenalic compounds.

• Korean Journal of Plant Tissue Culture
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• v.26 no.4
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• pp.271-274
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• 1999

This study was undertaken to develop an efficient propagation technique for mature Betula davurica. Using aseptic materials taken from in vitro culture, the effects of media and plant growth regulators on shoot proliferation and rooting were investigated. DKW medium turned out to be the best in shoot proliferation among the media tested. Whereas axillary buds were better culture material than apical buds in proliferation of shoots, apical buds were slightly better than axillary buds on shoot elongation. Neither 1 /2 MS nor WPM medium seemed to be suitable for shoot multiplication or elongation. When the explants were cultured on 1/2 MS medium, shoot elongation was retarded by forming big callus at the base. In the case of WPM, shoots could be formed normally, but they exhibited slow growing. NAA was so effective on in vitro rooting that more than 80% rooting could be achieved on half-strength DKW medium supplemented with 1.0 mg/L NAA after 4 weeks in cultures. Ex vitro rooting using elongated shoot was also applicable to rooting and acclimatization. Rooted plantlets were successfully acclimatized in an artificial soil mixture and grew normally. The results demonstrate that efficient mass propagation of mature B. davurica can be done through tissue culture.

• Journal of Plant Biotechnology
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• v.34 no.2
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• pp.161-166
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• 2007

In vitro shoot regeneration and multiple shoot induction has been obtained from the stolen node explants in Eremochloa ophiuroides (Munro) Hack. The highest number of shoots ($10.66{\pm}0.21$) was observed from initial explants after one month culture duration on Murashige and Skoog (MS) medium containing 6-benzyladenine (BA: 0.5 mg/l). First generation shoot was excised and sub-cultured on the same fresh media for further multiplication of shoots. An enhanced number of second round shoots ($15.33{\pm}0.21$) was obtained compared to the initial culture media containing BA (0.5 mg/l). The number of shoots/stolon node was higher among all the concentrations of BA than kinetin (KN). In vitro regenerated shoots were successfully rooted in the phytohormone free MS medium. Plantlets generated with roots were transferred to pots containing compound mixture of soil and kept in green house conditions. Acclimatized plants showed 100% survival rate with normal morphology in green house conditions. The present study demonstrates the effect of explant and different plant growth regulators towards in vitro response in E. ophiuroides. Moreover, the study reveals the effect of cytokinin on induction of shoot number per stolen node explant in E. ophiuroides.

• Plant Biotechnology Reports
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• v.5 no.2
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• pp.177-186
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• 2011

This study describes for the first time in Pinus genus a plant regeneration system via a combined pathway of somatic embryogenesis and organogenesis from immature seeds of radiata pine. Somatic embryos were obtained from embryogenic line 2162 of Pinus radiata D. Don on EDM basal medium containing $60{\mu}M$ ABA and 6% sucrose. The explants used for organogenesis experiments were either freshly collected somatic embryos or somatic embryos germinated for 1 week. Germination medium was half-strength LP medium, supplemented with 0.2% activated charcoal. Different induction periods and BA concentrations were assayed for shoot induction. After induction treatments, explants were elongated on the same medium used for germination stage. Rooting medium was quarter-strength LP medium supplemented with three different auxin treatments: $1.5mg\;L^{-1}$ 1-naphthalene acetic acid (NAA), $1.5mg\;L^{-1}$ indole-3-butyric acid (IBA) and $1mg\;L^{-1}$ IBA with $0.5mg\;L^{-1}$ NAA (MIX). The effect of the photon flux ($120mmol\;m^{-2}\;s^{-1}$ and darkness) in the first week of the explants in the rooting media was also tested. This methodology could offer an alternative to overcome some problems associated with somatic embryogenesis such as the seasonality of embryogenic tissue (ET) initiation or a low embryo production from the ET, a particularly important issue in the case of genetically transformed ETs.

• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.51-55
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• 2000

To investigate the effect of media and growth regulators in micropropagation of persimmon (Diospyros kaki Thunb.), dormant axillary buds taken from trees of persimmon cultivars such as Ichikikeijiro, Tonawase and Hiratenenashi were used. Shoot tips were successfully cultured in full or half of nitrogen strength of MS medium. The most effective cytokinins for shoot proliferation and elongation of persimmon cv. Ichikikeijiro were 5 mg/L and 2 mg/L zeatin, respectively. Shoots were successfully rooted in 1/2N-MS medium with 1 mg/L IBA.