• Korean Journal of Plant Tissue Culture
• /
• v.26 no.2
• /
• pp.93-97
• /
• 1999

Shoot tips with 2 leaf primordia were cultured to induce shoot primordia in MS liquid medium supplemented with several concentrations of BA and hIAA under the conditions of 10,000 lux illuminations for 24 h and of vertical shaking of 2 rpm in carrot. Two F$_1$ hybrids and two male sterility lines were used. Shoot primordia were only induced in the medium supplemented with 2.0 mg/L of BA and 0.2 mg/L of NAA. Genotypic specificity and seasonal effect of donor parents on shoot primordia induction were not observed and average 15-20% of the planted dornes developed to shoot primordia. The induced shoot primordia were successfully propagated by subculture in the same medium. However, they were grown into three different types during multiplication, that is, the type with multiple small shoots on the surface, the type of without any shoot, and the type of callus. Shoot primordia clusters with small shoots on the surface differentiated multiple shoots successfully in 1/2 MS solid medium supplemented with 0.2 to 1.0 mg/L of IAA and 0.2 to 1.0 mg/L of kinetin. New shoot primordia with small shoots were well formed when pieces bigger than 2 mm in diameter of the out layer of the shoot primordia cluster with small shoots were subcultured. No differences of multiplication and shooting ability and chromosomal variation of shoot primordia were observed until the 13th sub-culture.

• Horticultural Science & Technology
• /
• v.16 no.4
• /
• pp.525-527
• /
• 1998

This study was conducted to determine the optimum cultural condition and method for in vitro mass production of Hibiscus syriacus L. 'Honghwarang'. When callus induced in MS solid medium supplemented with 0.01 mg/L TDZ was cultured in liquid medium containing 0.01mg/L TDZ, callus growth and shoot primordia formation was most effective. Formed shoot primordia were regenerated into shoot in MS or 1/2 MS medium of growth regulator-free condition. Effects of mesh size, shaking speed on callus and shoot primordia formation were examined after 5 weeks. Callus and shoot primordia formation was formed most effectively at 10 mesh and 80 rpm shaking speed in liquid medium.

• Horticultural Science & Technology
• /
• v.16 no.4
• /
• pp.520-524
• /
• 1998

This study was carried out to investigate the effect of thidiazuron(TDZ) on callus and shoot primordia formation, to determine the most optimum multiple shoot induction medium, and to obtain the plantlets on solid medium via shoot organogenesis. TDZ 0.01 mg/L in MS medium was most effective on callus formation, and BA 0.1 mg/L was most effective on shoot growth, while TDZ 0.01 mg/L was most effective on callus formation. TDZ 0.001 mg/L was most effective in shoot primordia formation. Shoot tips were cultured with TDZ 0.01 mg/L for 8 weeks and induced callus was transferred to regeneration medium containing TDZ 0.001 mg/L. After 4 weeks induced shoot primordia were resubcultured at growth regulator-free medium for 4 weeks. The induced multiple shoots rooted more efficiently at NAA 1.0, 5.0 mg/L, or IBA 5.0 mg/L.

• Journal of Korean Society of Forest Science
• /
• v.78 no.4
• /
• pp.412-418
• /
• 1989

The stem segments of Ailanthus altissima were cultured on the Murashige & Skoog's medium(1962) supplemented with 0.1 mg/l BAP and 1.0 mg/l 2, 4-D for callus induction and proliferation, Shoot primordia were observed as greenish regions on the surface of yellow-brown calli about 8 weeks after culture. Shoot primordia were selected and transferred to the MS media containing various combination of BAP and 2, 4-D. Among these combinations the shoot primordia cell clusters on the medium added to 0.5mg/l BAP and 0.01mg/l 2, 4-D exhibited the highest number of shoot formation. These shoots were successfully transferred on the solid MS medium with no growth regulators for the rootings.

• Journal of Korean Society of Forest Science
• /
• v.94 no.2 s.159
• /
• pp.67-72
• /
• 2005

The objectives of this study were to identify the period of initiation of floral primordia in black locust (Robinia pseudoacacia L.) and subsequent development of floral buds until following spring. Four mature trees of black locust located in Suwon, Korea were selected. Bud samples were collected from the current-year shoots, starting from mid June to July every week, from August to October and from February to April every month. The buds were fixed in FAA solution, dehydrated, and imbedded in paraffin for microscopic observation. Buds collected on June 16, and 23, 1997, contained primitive primordia that might be interpreted as early floral primordia. By June 30, a bud showed a positive indication of inflorescence primordium with a well-formed shoot apex. All the inflorescence primordia observed throughout the collection periods were always associated with unique hairy appendages around the primordium and enclosed within a sclerenchymatous chamber. By July 7 and 15, a floral apex had early bud scales. By July 22, primitive inflorescence developed into visible arrangement of individual floral primordial By July 29, the inflorescence developed into whirl arrangement of individual floral primordia in a transverse section, but showed little further development until October 15. The inflorescence primordia seemed to over-winter at this stage. Buds collected from February 15 and March 24 the following year also showed no further development of inflorescence primordia. By April 7 the inflorescence started to show further development with elongated axis. At this time individual flowers were easily recognized.

• Korean Journal of Medicinal Crop Science
• /
• v.7 no.4
• /
• pp.296-302
• /
• 1999

This experiment was conducted to study the effect of $CO_2$(0, 2, 500, 5, 000, 10, 000ppm) enrichment by enabling ventilation on micropropagation of multi-shoot and on the saponin contents in vitro in Korean ginseng (Panax ginseng C. A. Meyer). Embryo was cultured in Murashige and Skoog medium added 3mg/ l of Indolbutyric acid, Benzyladenin and Gibberellic acid $(GA_3)$, respectively. $CO_2$, enrichment had little effects on the number of adventitious buds and shoots originated from adventitious buds. The ratio of differentiated shoots to adventitious buds were about 50% in $CO_2$, enrichment treatment. The shoots originated from adventitious bud showed more rapid growth and had larger leaf area than the shoots originated from the leaf primordia did. The number of shoot primordia was the highest in 2, 500ppm of $CO_2$ enrichment treatment. On the contrary, 10,000ppm of $CO_2$, enrichment made smaller the number of shoot primordia and ratio of shoots to shoot primordia. The range of shoots differentiated was from shoot primordia were 15. 4 to 23. 9. The rate of dry weight of cultured shoots showed lowest (7. 5%) in control and highest (8. 59%) in 2, 500ppm of $CO_2$, enrichment. Rate of in vitro flower in control was 7.6% and that in 2500ppm of $CO_2$ was about twice (15.7-16.3%) as much as in control. Flower number per a embryo cultured was about 1.2-1.3. In the multi-shoots with callus enriched by 2, 500ppm of $CO_2$, the contents of crude saponin and ginsenosides in multi-shoots alone were higher than in multi-shoots with callus. The characteristics of ginsenosides in multi-shoots were especially the higher content of ginsenoside Rd, Re, and $Rg_1$.

• Korean Journal of Plant Tissue Culture
• /
• v.24 no.5
• /
• pp.263-268
• /
• 1997

Effects of plant growth regulators and condition on shoot induction from internode explants of Actinidia arguta were investigated. Optimal condition for shoot induction was obtained when internode explants were cultured on MS medium containing 3.0 mg/L zeatin. The frequency showed about 62.5% under darks condition at 27$^{\circ}C$ after 6 weeks of culture. Regenerated shoots were rooted on WPM medium supplemented with 0.5 mg/L NAA and the regenerants were acclimated to an artificial soil with mixture (perlite : vermiculite = 1:1, v/v) for further growth and successfully transplanted to the soil in a highly humidified greenhouse. Histological observations revealed that meristemoids were formed from small and isodiametric cells, and then developed to shoot primordia.

• Korean Journal of Plant Resources
• /
• v.19 no.2
• /
• pp.265-272
• /
• 2006

This study was conducted to investigate the efficient propagation method of Cyrtomium caryoptideum var. coreanum by sporophyte culture. The influence of origin of explant sources (rhizome, blade, or stipe) and homogenization of culture materials on shoot regeneration were investigated. As a result, only rhizome explant exhibited the organogenic capacity and the shoot regeneration was promoted by homogenization of culture material. Vigorous and excellent growth of multiple shoots was induced on the half-strength of inorganic salts containing MS medium. It was appeared that optimum nitrogen content of shoot regeneration was half-strength of nitrogen containing MS medium (30mM) and optimum sucrose concentration was 1%. Addition of $NaH_2PO_4$ to culture medium generally enhanced shoot multiplication and promoted growth of the regenerants. The organogenic capacity of homogenized rhizomes was especially promoted on medium supplemented with $5{\mu}M$ kinetin plus $5{\mu}M$ IBA. The incorporation of $0.1\sim0.2%$ activated charcoal on medium supplemented with growth regulators prevented the formation of multiple bud primordia - nodule-like bud clusters and improved the normal morphogenesis of sporophytes.

• Journal of Plant Biotechnology
• /
• v.32 no.4
• /
• pp.301-306
• /
• 2005

Conditions for efficient organogenesis and plant regeneration from Dianthus gratianopol suspension cultured cells were established. Shoot-forming calli of glossy surface, pale green and knobby type were selected from leaf explant-derived calli and were suspension-subcultured every week in CP liquid medium with 1.0 mg/L 2,4-D and 0.5 mg/L BAP. Combinations of 1.0 mg/L 2,4-D and 0.5 mg/L BAP, and 1.5 mg/L 2,4-D and 0.5 mg/L BAP were effective for the induction of regenerative callus from the suspension cultured cell clusters. Multiple shoot primordia were initiated from the green spots of these regenerative callus and formed shoots on MS medium with 1.0 mg/L TDZ and 0.5 mg/L PAA. Shoot regeneration frequency (calli regenerating at least one shoot) was about 87%. For plant regeneration, proliferated shoots were excised and transferred to MS medium with 0.1 mg/L NAA for root initiation after 9 weeks of culture. The regenerants were potted in soil and formed the flowering buds and petals. Also, adventitious shoots were formed from the excised green shoot primordia of regenerative callus and these shoots proliferated successfully and regenerated to whole plants.

• Molecules and Cells
• /
• v.38 no.3
• /
• pp.243-250
• /
• 2015

Patterning of the polar axis during the early leaf developmental stage is established by cell-to-cell communication between the shoot apical meristem (SAM) and the leaf primordia. In a previous study, we showed that the DRL1 gene, which encodes a homolog of the Elongator-associated protein KTI12 of yeast, acts as a positive regulator of adaxial leaf patterning and shoot meristem activity. To determine the evolutionally conserved functions of DRL1, we performed a comparison of the deduced amino acid sequence of DRL1 and its yeast homolog, KTI12, and found that while overall homology was low, well-conserved domains were presented. DRL1 contained two conserved plant-specific domains. Expression of the DRL1 gene in a yeast KTI12-deficient yeast mutant suppressed the growth retardation phenotype, but did not rescue the caffeine sensitivity, indicating that the role of Arabidopsis Elongator-associated protein is partially conserved with yeast KTI12, but may have changed between yeast and plants in response to caffeine during the course of evolution. In addition, elevated expression of DRL1 gene triggered zymocin sensitivity, while overexpression of KTI12 maintained zymocin resistance, indicating that the function of Arabidopsis DRL1 may not overlap with yeast KTI12 with regards to toxin sensitivity. In this study, expression analysis showed that class-I KNOX genes were downregulated in the shoot apex, and that YAB and KAN were upregulated in leaves of the Arabidopsis drl1- 101 mutant. Our results provide insight into the communication network between the SAM and leaf primordia required for the establishment of leaf polarity by mediating histone acetylation or through other mechanisms.