• Korean Journal of Agricultural Science
• /
• v.14 no.2
• /
• pp.205-212
• /
• 1987

To examine the morphogenetic response, stem segments of 8 Populus spp. and 3 different explants of P. nigra var. italica were cultured on MS (Murashige and Skoog 1962) and WPM (Woody Plant Medium) medium containing various phytohormones. The results obtained were as follows: 1. Shoot regeneration and development from stem segment of 8 Populus spp. showed a quite difference according to the section and the species. All of the species of Leuce and Tacamahaca section did not form adventitious buds, while most of explants showed axillary or dormant bud elongation after 4 weeks. But P. nigra var. italica of Aigeiros section showed a successful adventitious bud formation (mean 5.4 buds per explant). 2. Leaf, petiole, and internode segment of P. nigra var. italica showed a quite differences according to media and ex plants upon the morphogenetic response. Adventitious bud formation from leaf was more abundant and readily initiated on the abaxial side than on the adaxial side. Mean number of 103 adventitious buds per explant was obtained from abaxial side of leaf segment cultured on WPM medium containing $0.2mg/{\ell}$ BAP for 5 weeks. 3. 2,4-D (2,4-dichlorophenoxy acetic acid) supplemented to media appeared to be negative upon the adventitious bud formation of P. nigra var. italica, while it promoted callus formation from all explants. Especially, NAA (${\alpha}$-naphtalene acetic acid) or NAA combination with BAP (6-benzylaminopurine) promoted root regeneration from the all explant of P. nigra var. italica in this study.

• Proceedings of the Korean Society of Plant Biotechnology Conference
• /
• 2005.04a
• /
• pp.6-9
• /
• 2005

Plant biotechnology involving genetic modification has been rather controversial. However, the major issues related to safety are being addressed by continued improvements in technology. Some of the related facts will be highlighted to set the tone for a scientific discussion on the possibilities of using the technology for crop improvement. Our main research interest is to understand the molecular regulation of shoot bud regeneration in plant tissue culture, which is essential for crop improvement by biotechnology. We have isolated and characterized some genes that are associated with adventitious shoot regeneration. These include a MADS-box cDNA (PkMADS1) from paulownia kawakamii, which regulates vegetative shoot development and in vitro shoot regeneration from leaf explants. Another gene we have characterized from petunia codesfor a cytokinin binding protein (PETCBP). Preliminary functional analysis of this gene indicated that this also affects adventitious shoot bud initiation. Also, the antisense suppression of this gene in petunia causedexcessive branching. Results from our work and selected other publications will be used to highlight the possibilities of manipulation of such genes to improve crop species.

• Journal of Plant Biotechnology
• /
• v.31 no.1
• /
• pp.49-53
• /
• 2004

Shoot formation was investigated from in vitro cultivation of exotic hybrid poplar (Populus koreana ${\times}$ P. trichocarpa) with a specific stomatal character occurring both upper and lower surface of leaves. Two different explants (stem and leaf segment) of Peace poplar were cultured on half strength Murashige and Skoog (MS) basal medium supplemented with the various concentrations of thidiazuron as a plant growth regulator. Most adventitious shoots were produced from excised ends of stem or mid-veins of leaf segments. The highest average numbers of shoots were 7.1 and 5.3 with the treatments of 0.02mg/L TDZ in both explants of stem and leaf segment. The highest shooting rates were achieved to 83.3％ and 47.6％ with the concentrations of 0.01mg/L and 0.02mg/L TDZ by axillary bud and leaf cultures, respectively.

• Journal of Plant Biotechnology
• /
• v.5 no.4
• /
• pp.225-231
• /
• 2003

The hormonal requirement suiting micropropagation of Morus alba during any season throughout the year was studied. Sprouting frequency from axillary buds of M. alba was greatly influenced by the time of explant collection, the highest value was achieved when nodal explants were collected at the end of bud dormancy period (late in March) and cultured on Murashige and Skoog (MS) medium supplemented with low concentration (0.5 mg/L) of BAP, kinetin or IBA (85-68%). In addition, they showed higher axillary bud sprouting on growth-regulators-free medium (49%) than others collected in autumn or winter and cultured on medium supplemented with various growth regulators (47-48%). Regardless of that period, young explants with greenish buds collected in summer exhibiting high sprouting frequency (66%) on MS medium supplemented with 0.5 mg/L kinetin and 0.5 mg/L GA3. Shoot multiplication via adventitious bud formation was achieved when the nodal explants were cultured on MS medium supplemented with 2 mg/L BAP and 0.2 mg/L IBA. Further multiplication via nodal explants of in vitro grown shoots was obtained on MS medium supplemented with 0.5 mglL BAP and 0.5 mg/L GA3. While half strength MS medium supplemented with low concentration (0.5 mg/L) of IBA, IAA or 2,4-D stimulated adventitious root formation, IBA was the best. After transfer the plantlets to the soil, acclimatization for three weeks was essential prerequisite for survival in high frequency (92%). Peroxidase activity is related to break of bud dormancy where maximum enzyme activity was detected when the lateral buds were induced to commence growth under field condition (early in spring) or in vitro.

• Journal of Plant Biotechnology
• /
• v.30 no.1
• /
• pp.53-58
• /
• 2003

This study was performed to investigate the effects of various media compositions in regeneration of Lilium lancifolium. The adventitious bud initiation from microscale was the best on MS medium supplemented with BAP 1.0 mg/L and NAA 0.1 mg/L after 4 weeks of culture. However, from bulbscales, adventitious bud initiation was the best in dark condition on MS medium supplemented with BAP 0.5 mg/L and NAA 0.1 mg/L. On the other hand, callus induction was found to be the best from the microscales incubated in complete dark condition for 8 weeks on MS medium supplemented with 2,4-D 1.0 mg/L and BAP 0.1 mg/L. The highest plantlet regeneration from callus was obtained after incubation in the light condition for 8 weeks on MS medium supplemented with NAA 0.5 mg/L and BAP 0.1 mg/L. Rooting of shoots was obtained easily on MS medium and the plantlets were transferred to soil pots after 8 weeks. The chromosome analysis of the root tip cells was revealed that the callus-derived plantlets had normal chromosome number, 2n=24. No variation was observed in the morphology of the plantlets.

• Journal of Plant Biotechnology
• /
• v.6 no.3
• /
• pp.171-179
• /
• 2004

Hormonal requirements inducing different regeneration pathways with particular emphasis on somatic embryo-genesis in Alhagi graecorum were studied. While combination of 0.5 $\mu{M}$ 2,4-dichlorophenoxyacetic acid (2,4-D), 2.5 $\mu{M}$ 6-benzylaminopurine (BAP) and 5 $\mu{M}$ 1-naphthaleneacetic acid (NAA) in MS medium induced callus formation and callus maintenance from internodal explants, each alone or in combination with other induced distinct regeneration pathway. Adventitious bud formation was induced on MS medium supplemented with 2.5 $\mu{M}$ BAP. It was improved when 2.5 $\mu{M}$ BAP was used in combination with 5 $\mu{M}$ NAA. MS medium containing 0.5 $\mu{M}$ 2,4-D or 5 $\mu{M}$ NAA induced the formation of abnormal direct somatic embryos. While increase of 2,4-D concentration (1.125-9) resulted in the formation of viable embryogenic mass, increase of NAA did not change its effect. NAA should be used in combination with 2,4-D even at low concentration (0.5 $\mu{M}$) to form embryogenic mass. In A. gaecorum, the role of 2,4-D as trigger of somatic embryogenesis and BAP as trigger of adventitious bud formation was deduced, but for maximum yield certain auxin-cytokinin ratio should be applied. Embryogenic masses characterized by high water content, low peroxidase activity, and low number of peroxidase and glutamate oxaloacetate transaminase bands in comparison with calli obtained under conditions stimulating adventitious bud formation. The resulted differential gene expression, which could be detected by native-PAGE patterns, could be used as marker for organogenic pathway in A. graecorum.

• Journal of Plant Biotechnology
• /
• v.5 no.4
• /
• pp.245-250
• /
• 2003

An efficient procedure was developed for adventitious shoot bud induction and plantlet regeneration from various explants of the ten genotypes of Pepper (Capsicum annuum L.) using Thidiazuron (TDZ). Among various treatments at 1.0-3.0 mg/L TDZ Induced maximum number of adventitious shoots depending upon the explant type and genotype compared to other treatments. Among the explants tested, leaf induced maximum number of adventitious shoots than the cotyledons. TDZ-mediated organo-genesis was possible in 10 pepper cultivars, the extent of the response being genotype-dependent. Of the ten genotypes tested, C. annuum cvs CA960, $G_4$ and X-235 were produced maximum number of adventitious shoots and Sell was the least, and all other genotypes gave moderate response. Elongation of multiple shoots was observed on medium supplemented with SA (0.05 mg/L) in combination of IAA (0.05 mg/L). Differences in ability for in vitro shoot regeneration and elongation depend upon the variety and explant type. The elongated shoots were success. Fully rooted on MS medium containing at 1.0 mG/L IAA. Plantlets regenerated from different explants of ten genotypes were found to be diploid (2n=24) and were devoid of any chromosomal aberrations. Regenerated plants were successfully established in soil where 85-90% of them developed into morphologically normal and fertile plants.

• Proceedings of the Korean Society of Plant Biotechnology Conference
• /
• 2005.04a
• /
• pp.137-137
• /
• 2005

• Korean Journal of Medicinal Crop Science
• /
• v.13 no.6
• /
• pp.273-277
• /
• 2005

Adventitious shoots were directly induced from leaf explants of R. glutinosa, an important medicinal plant. Proliferating shoot cultures were obtained by culturing leaf discs on Murashige and Skoog(MS) medium alone or combination with auxins and cytokinins. MS medium supplemented with 1 $mg/{\ell}\;BA\;and\;2\;mg/{\ell}$ IAA was the most effective, providing high shoot bud formation frequency without formation of intervening callus. The effect of leaf age on adventitious shoot formation was also investigated. The maximum shoot bud production (93.4%) was achived using 3rd leaf from apex of 6 weeks old plantlets after seed germination. Plantlet were rooted on an half-strength MS (1/2MS) medium containing 0.1 $mg/{\ell}\;IBA$. This prtocol is useful for clonal propagation and Agrobacterium-mediated transforamtion in R. glutinosa.

• Korean Journal of Plant Tissue Culture
• /
• v.22 no.4
• /
• pp.223-227
• /
• 1995

Immature flowers and lateral buds of Neoregeria carorinae cv. Tricolor were cultured for micropropagation and the collecting times of materials, growth regulators and theirs concentrations, and cultural methods on the formation of adventitious buds and growth were investigated in this experiment The formation rate was the highest in immature flowers collected at 4weeks after flower bud differentiation and in buds at 7weeks after flower differentiation of adventitious buds. MS medium supplemented with 1.0 mg/L BA and 0.5 mg/L BA was the most favorable for the formation of adventitious buds. Solid medium was more effective for the formation of adventitious buds than liquid one. MS medium with 1.0 mg/L NAA was the most suitable for the rooting of regenerated shoot. Liquid medium was effective for the rooting of regenerated shoot than solid one.