• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.261-269
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• 1997

Excised immature ovules and calli derived from the stems of cottonwood were bombarded with microprojectiles carrying plasmid DNA containing CaMV-35S promoter and ${\beta}$-glucuronidase(GUS) gene. After bombarded, the expression of GUS gene was detected by the assay of 5-bromo-4-chloro-3-indolyl-${\beta}$-gluconide(X-gluc). Transient gene expression was measured by counting the number of distinct regions of GUS activity per explant. As major parameters, the number of shots and the period of exposure to X-gluc after the bombardment were investigated for detecting GUS gene expression. In this experiment, the percents of GUS gene expression showing spots were 56.8 from immature ovules and 75.9 from micro-calli of cottonwood species. Among the treatments, two consecutive shots and 48 hour exposure produced about $25.75{\pm}2.77$(per ovule), $11.43{\pm}1.22$(per mini petridish) spots, respectively, Microprojectile particle bombardment provides a useful method to assay transient expression in both types of explants. Furthermore, our results represent that the excised ovule and/or the calli might be stably transformed by the biolistics.

• Journal of Plant Biotechnology
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• v.33 no.4
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• pp.297-302
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• 2006

In general, the proliferation of orchids via somatic embryos has been used for mass production of somatic clones because of high propagation efficiency. In spite of high propagation rate, this method often brings somaclonal variation, especially polyploid frequency. Therefor we here concentrated to investigate the relationship between endopolyploidization patterns of explants and the occurrence of tetraploid variant in clonally proliferated Doritaenopsis via somatic embryo regeneration system. In the fully developed somatic embryo, upper part contained 2C to 16C while middle and lower parts showed 2C to 32C DNA content. Two-week-old embryo contained 2C to 16C, whereas those regenerated after 4 to 10-week-old contained 2C to 64C nuclei. Results showed that endoreduplication was variable depending upon tissue types, ages, and parts in one species. lower part of somatic embryo having high endoreduplication degree increased the regeneration of tetraploid variants by about 3-fold comparing to upper part of somatic embryo culture. polyploid frequency occurrence might be closely related to the high levels of endoreduplication of somatic embryos used as explant. It suggested that the upper part of somatic embryo having comparatively low endoreduplication degree is suitable for the stable in vitro propagation system.

• Archives of Pharmacal Research
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• v.16 no.3
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• pp.244-250
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• 1993

Calli and suspension cultures were obtained following inoculation of the explant from leaves of Ginkgo biloba L on the supplemented MS basal medium. The obtained calli and suspension cultured cells were able to produce detectable amounts of ginkgolides which are known as natural specific PAF antagonists. The production of ginkgolides in the calli and suspension cultured celles were identified using GC/MS, GC and HPLC with authentic ocmpounds. Since the production of ginkgolides A and B the calli and suspension cultured cells had been confirmed, effects of types and concentration of plant growth regulators, media and illumination on the induction and growth of the callus were studied. The concentrations of growth regulators for optimal callus were studied. The concentrations of growth regulators for optimal callus induction were studied. The concentrations of growth regulators for optimal callus induction were 1.0 to 2.0 mg/L for NAA and o.1 mg/L for kinetin. The growth of the Callus seemed to be more simnultaed with the combination of NAA and kinetin than NAA and BA with illumination at all concentration ranges of 1.0 to 4.0 mg/l for NAA and o.1 to 1.0 mg/L for kinetin or BA studied. Amogn 8 different media used, the induction rate of callus on Anderson, Eriksson, and Shenk and Hildebrant at 4 weeks after the innoculation was almost the same as that of MS. However, callus was rarely induced on Heller or White medium. Suspension cultures were easily initiated with 3 g of callus (fresh weight) derived from ginkgo leaves on supplemented MS medium. A typical growth curve of suspension cultured cells could be obtained by measuring the fresh weight of the suspension cultured cells at every 3 days. To improve the growth of suspension cultured cells of ginkgo, effects of concentrations of NAA, sucrose, phosphate ions and molar ratio of $NH_{4}^+\;to\;NO_{3}^-$ ions in the culture medium were studied. The maximum growth of the cells was achieved when the culture medium contained 1.0 mg/L of NAA, 30 g/L sucrose, 1.75 mM phosphate ions and 1:5 molar ratio of $NH_{4}\;to\;NO_{3}^-$ ions.

• Molecules and Cells
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• v.23 no.3
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• pp.323-330
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• 2007

The mature wheat embryo is arguably one of the best explants for genetic transformation because of its unlimited availability and lack of growth season restriction. However, an efficient regeneration system using mature wheat embryos (Triticum aestivum L.) is still not available. To identify genes related to the tissue culture response (TCR) of wheat, QTLs for callus induction from mature embryos and callus regeneration were mapped using an RIL population derived from the cross of 'Wangshuibai' with 'Nanda2419', which has a good TCR. By whole genome scanning we identified five, four and four chromosome regions conditioning, respectively, percent embryos forming a callus (PEFC), percent calli regenerating plantlets (PCRP), and number of plantlets per regenerating callus (NPRC). The major QTLs QPefc.nau-2A and QPcrp.nau-2A were mapped to the long arm of chromosome 2A, explaining up to 22.8% and 17.6% of the respective phenotypic variance. Moreover, two major QTLs for NPRC were detected on chromosomes 2D and 5D; these together explained 51.6% of the phenotypic variance. We found that chromosomes 2A, 2D, 5A, 5B and 5D were associated via different intervals with at least two of the three TCR indexes used. Based on this study and other reports, the TCRs of different explant types of wheat may be under the control of shared or tightly linked genes, while different genes or gene combinations may govern the stages from callus induction to plantlet regeneration. The importance of group 2 and 5 chromosomes in controlling the TCRs of Triticeae crops and the likely conservation of the corresponding genes in cereals are discussed.

• FLOWER RESEARCH JOURNAL
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• v.17 no.2
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• pp.93-100
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• 2009

This study was carried out to investigate the efficient in vitro mass propagation methods for juvenile sporophytes of Matteuccia struthiopteris. Chopped segments of pinnae, petiole and rhizome were cultured on 1/2MS with 0.1% activated charcoal. Among these explant sources only rhizome segments produced young sporophytes, regenerating vigorously on 1/2 MS medium. Adjusting sucrose concentration to 2% and supplement to $50mgL^{-1}$ $NaH_2PO_4$ in 1/2MS medium proved to be more efficient for plant regeneration. Various combinations of growth regulators such as kinetin, BA, NAA, and IBA were added to the growing media, and the best sporophyte regeneration was obtained by $1{\mu}M$ kinetin. The BA addition resulted in vigorous proliferation of meristematic tissues, but without differentiation to sporophytes. Three types of culture methods, solid using agar, liquid stationary, and liquid shaking culture, were employed with or without activated charcoal. The addition of 0.1% activated charcoal to modified 1/2MS media (2% sucrose, $50mgL^{-1}$ $NaH_2PO_4$, $1{\mu}M$ kinetin, pH 5.8 and 0.8% agar) yielded highest sporophyte regeneration in liquid shaking culture.

• Journal of Plant Biotechnology
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• v.49 no.1
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• pp.82-89
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• 2022

In vitro techniques were developed for propagating Vaccinium oldhamii using shoots with apical buds. Explants having an apical bud were cultured on Murashige and Skoog (MS) medium supplemented with 1.0, 2.0, and 5.0 mg/L of each zeatin, thidiazuron, 6-benzylaminopurine (BA), and 6-(γ,γ-dimethylallylamino)purine (2-iP) in order to induce multiple shoots. Among the tested treatments, the 2.0 mg/L of 2-iP proved to be most suited for the multiplication and growth of shoots; the multiple shoot induction rate was 100.0%, the average number of shoots was 7.4 per explant, and the average shoot length was 51.7 mm. The in vitro elongated shoots were rooted on half-strength MS medium containing various concentrations of indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA). However, overall callus overgrowth was observed in all treatments and resulted in necrosis and abnormal shoot growth in root formation. A low concentration (0.5 mg/L) of IBA was appropriate for normal root development and the in vitro rooting rate was 30%. Ex vitro treatments on root formation using various concentrations of IBA with Talc powder and two types of rooting substrates (Flexi-Plugs or Horticultural soil) were examined. The ex vitro rooting rate (80%) and length of roots (32.9 mm) were obtained when the cut ends of the shoots were treated with 1.0 mg/L IBA and cultivated in Horticultural soil for 2 months. These findings suggest that ex vitro rooting is the more effective method for improving root formation in Vaccinium oldhamii than in vitro rooting.