• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.31-35
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• 2004

In order to develop an efficient micropropagation technique for an endangered species, Stellera rosea N., stem node cultures were conducted on MS medium supplemented with cytokinins. Generally, BA was better than zeatin on shoot proliferation from stem nodes, whereas zeatin showed more effective on shoot elongation. In vitro rooting of shoots was achieved by application of an auxin pre-culturing method. Overall rooting rate was relatively low and differed depending on the culture period. Pre-culturing of shoots for 15 days at 1.0mg/L IBA revealed a slightly better rooting efficiency reaching 30％ rooting rate than NAA. Root induction rate by NAA also varied with concentration of NAA and culture periods. Total 51％ of the rooted plantlets survived on artificial soil mixture and grew normally without any distinct morphological variation. The results suggest that the endangered Stetllera plants are propagated via in vitro culture system, but still need to more study for the improvement of rooting and acclimatization of the plantlets in soil.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.55-59
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• 2007

The study was carried out to develop transformants resisting to Phyophthora blight disease in the domestic pepper cultivar Subicho. In transforming of syn600 promoter with elicitin gene using Agrobacterium (LBA4404/pBI101 syn600-syn${\alpha}$-elicitin) to cotyledons of pepper, rate of shoot formation in 'Subicho' was 11.1% in medium containing 3 mg/L zeatin and 0.05 mg/L NAA, and also 12.8% in medium containing combination of 4 mg/L zeatin and 0.05 mg/L MAA. For PCR reaction using elicitin gene primer of transformants regenerated from cotyledons, we detected a specific band of 536 bp, and also showed strong signal at position of 536 bp in accordance with NPTII gene used as probe in Southern blot. Transformants pepper shown resistance to blight fungus was inoculated to seedlings of the $T_{1}\;and\;T_{2}$ transformants by concentration (density: zoo spore $10^{3}/mL$).

• Journal of Ginseng Research
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• v.20 no.1
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• pp.83-87
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• 1996

The effects of gibberilin ($GA_3$) on levels of endogenous indole-3-acetic acid (IAA) and zeatin in both fresh and stratified American ginseng (Panax quinquefolium) seeds were investigated. In our first experiment, the fresh seeds were stratified after soaked in 80 ppd $GA_3$ solution for 24 hours. We found that the IAA concentration in embryo increased by 50.7% and 82.1% respectively at the 120th day and the 188th day of stratification, and the zeatin concentration also increased by 3.8% and 51.6% respectively. In our second experiment, we treated the seeds after 134 days stratification with 80 ppm GA3 for 24 hours and then continued to stratify them. We found that the IAA concentration in embryo increased by 32.9% and 17.7% respectively at the 164th day and the 208th day of stratification while zeatin concentration increased by 22.7% and 30.6% respectively In our another experiment, we studied the effects of $GA_3$, abscislc acid (ABA) and GA, plus ABA on germination rate of seeds treated with these plant hormones during stratification. We found that when the stratified seeds whose ratio of embryo had reached 75% were treated with 80 ppm GA3 for 24 hours and then were allowed to be stratified for another 88 days, the weight and length of embryo (p < 0.05), and germination rate (p < 0.01) increased. In contrast, the 25 ppm ABA treated with for 24 hours was found to Inhibit the growth of embryo (p < 0.05) and reduce the germination rate (p < 0.05) . The experiment of combination treatment of $GA_3$ and ABA showed that $GA_3$ could relieve the inhibitory effects of the ABA on the development of the seeds.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.141-146
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• 2001

Protoplasts were isolated from cotyledons, hypocotyls, and mesophyll tissues of three species of Capsicum species (C. anuumm, C. bacatuum, and C. chacoense). Combination of Cellulysin (1%) and Macero-zyme (0.25%) in 0.65 M sorbitol was found to be the most effective for the digestion of cell wall, regardless of the Capsicum species. Antioxidant MES (2-［N-Morpholino］ethanesulfonic acid) in the enzyme solution helped protoplasts overcome browning. After 5 days of initial culture, Cell division occurred in modified K8p medium containing 1~5 mg/L zeatin, 0.5 mg/L IAA, 0.1~0.5 mg/L TDZ, and 1 mg/L 2,4-D under continuous dark condition at $25^{\circ}C$. Semi-solid agarose culture method was more effective than liquid culture, and it also protected the cells from browning caused by polyphenolic compound released during protoplast culture. A total of 4000 calli were obtained from protoplast culture of different capsicum species. All of these calli were transferred to the 100 combinations of regeneration media using various plant growth regulators; TDZ, IAA, 2ip, BAP, NAA, and zeatin. These calli derived from protoplast of three species of capsicum were, however, not differentiated into shoots.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.159-164
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• 2001

To produce novel bioactive flavonoids, Gericudranin A and Gericudranin B, a cell culture system of Cudrania tricuspidata including callus induction and optimization of culture conditions was established. Friable calli were efficiently induced from the hypocotyl segments of seedlings on B5 medium supplemented with 1.0 mg/L NAA, 0.1 mg/L kinetin and 3% sucrose. Several factors were optimized for the Gericudranin production and the cell growth in suspension cultures. Low level of basal salt medium (1/8 MS), 1.0 mg/L IAA and 0.1 mg/L zeatin, and high level of sucrose (5%) were effective for the production of Gericudranins, whereas WPM with 1.0 mg/L NAA, 0.1 mg/L zeatin, and 5% sucrose were more effective for the cell growth. When cells were cultured on MS liquid medium supplemented with 1.0 mg/L IBA, about 2200 $\mu\textrm{g}$/g dry wt of Gericudranin A could be produced. The level might be about 10 times of the native inner bark. About 2350 $\mu\textrm{g}$/g dry wt of Gericudranin B was also produced on MS liquid medium with 5% sucrose, 1.0 mg/L NAA, 0.1 mg/L kinetin. The content was estimated about 3 times of the level of native inner bark.

• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.329-334
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• 1995

Transformation system of rolC gene, dwarf gene in Lycium chinenese Mill. established by using system. Pin-punctured leaves induced numerous adventious buds in abaxial side when cultured on 3/2 MS medium containing 2.0 mg/L zeatin. Survival rate and shoot regeneration frequency of leaf explants decreased as kanamycin sulfate level increased. Shoot buds were not regenerated on 3/2 MS medium containing 10 mg/L kanamycin sulfate and 2.0 mg/L zeaein. Of the level tested, 10 mg/L of kanamycin sulfate was optimum in selection of kanamycin sulfate resistant plant. Co-culture time of bacteria and leaf explants was affected at the frequency of shoot regeneration and survival of leaf explants. Leaf explants co-cultivated during above 48hr severely decreased survival rate and shooting rate. Best result on survival rate and shooting rate were obtained when exposed for 24 h. 80 explants of 105 leaf explants survived on 3/2 MS medium containing 2.0 mg/L zeatin and 10 mg/L kanamycin sulfate, and 15 shoots was regenerated on the same medium. To select kanamycin sulfate resistant plant, regenerate as cultured on 3/2 MS medium containing 10 mg/L kanamycin sulfate, and obtained 5 kanamycin resistant plants. Southern blot analysis conformed that the rolC gene was incorporated into the genomic DNA of kanamycin resistant plants.

• Journal of Plant Biotechnology
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• v.46 no.4
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• pp.303-309
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• 2019

A protocol for the in vitro propagation of Chamaecyparis obtusa was established in the present study. Multi-shoots were initiated from apical shoot explants from germinants after 10 weeks of culture on Litvay medium (LM) supplemented with different concentrations of cytokinin. The effects of pre-treatment with high concentrations of cytokinin and varying concentrations (0.2 to 5.0 mg/L) of zeatin on in vitro shoot elongation and shoot multiplication were investigated. Optimal shoot growth was achieved on LM medium, with over 10-mm shoots after 10 weeks of culture. In the anti-browning tests, ethanesulfonic acid triggered the least browning in the shoot tips. The highest multi-shoot induction was observed in the 0.5-mg/L zeatin treatments, which yielded 80% induction of shoots after 10 weeks of culture, and maximum shoot elongation was observed in the LM basal medium without the hormone. The highest rooting rates were 65% under 0.2 mg/L indole-3-butyric acid.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.34-39
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• 2007

Whole plants were regenerated from callus induced from leaf explants in hybrid kiwi (Actinidia deliciosa${\times}$A. arguta). Callus was induced from leaf explants which cultured on MS solid medium supplemented with combination of auxin (2,4-D, NAA: 0.1~0.5 mg/l) and cytokinin (BA: 0.1~0.2 mg/l). them, the highest callus formation (96.2%) was obtained from the treatment of 0.5 mg/1 2,4-D+0.1 mg/l NAA+0.05 mg/l BA. In the experiment of adventitious shoots induction from primary shoots, only a few shoots were produced in the treatment of 1.0 mg/l BA+0.05 mg/l IBA or 2.0 mg/l BA+0.05 mg/l lBA. As the callus were transferred to the secondary shoot-inducing medium, multiple shoots were obtained from the medium supplemented with 1.0, 2.0 or 5.0 mg/l zeatin in addition to the mixed treatments of BA, thidiazuron (TDZ) or zeatin. However, no multiple shoots were induced on the BA-contained medium of concentrations. Therefore it turned out that addition of BA to medium was less effective for induction of multiple shoots from callus in Actinidia deliciosa${\times}$A. arguta. For producing adventitious roots from shoots, the best frequency of rooting (83.3%) were recorded on the treatment of in vitro rooting (Standardi (St)+1.0 mg/l IBA). On the other side, the lowest result (40.0%) were shown in the treatment of 500 mg/l IBA, 1 hr. Whole plants with shoots and roots were recovered and acclimatized successfully.

• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.175-179
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• 2005

To develop a high efficiency plant regeneration system from in vitro cultures of strawberry, cv. Yeobong, petiole and leaf explants were cultured on MS basal medium containing a combination of 0.5 mg/L IBA and 3.2 mg/L kinetin or zeatin or benzyl amino purine (BAP) for 6 weeks, and leaf explants with dark pretreatment for a week ($T_1$), 2 weeks ($T_2$), and 4 weeks ($T_3$) were cultured on medium supplemented with 0.5 mg/L IBA and 3.2 mg/L zeatin under 16 hr photoperiod for 6 weeks. Shoot organogenesis was observed from the greenish calli containing minimal anthocyanin formed at proximal cutting edges of the leaf explant (57%) when cultured adaxial side on the medium, whereas was directly formed from a cutting edges of petiole explant (6.3%). Frequency of callus formation and shoot organogenesis at large size of leaf explant ($1.0{\sim}1.5\;cm^2$) was higher than small size ($0.5{\sim}1.0\;cm^2$), and dark pretreatment significantly improved the frequency of leaf explants that produced calli and shoots. The maximum frequency (87%) for shoot organogenesis was obtained from the leaf explants that transferred to a 16 hr photoperiod condition after the initial 4 weeks dark period. The improved frequency (87%) in comparision with control without dark pretreatment (27%). When the shoots were transferred to 1/2 MS basal medium, formed roots with 20 d of culture. The rooted plants were subsequently transferred to the pots and to the field.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.117-121
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• 2002

We have developed an in vitro micropropagation system via shoot formation from axillary buds using nodal segments of Corylopsis coreana. Explants from both juvenile tree (one-year-old greenhouse stock seedlings) and mature tree (ten-years-old tree in nursery) were compared with regard to propagation efficiency. Combined treatment of both BA and zeatin were effective on shoot proliferation since the best result was obtained on MS medium supplemented with 0.5∼3.0 mg/L zeatin and 0.2 mg/L BA. Generally, juvenile explants were better in both shoot proliferation and growth than mature explants. However, as the duration of in vitro culture was proceed to 6 months, explants from mature tree also produced three shoots per explant. Distinctive differences in rooting and adaptability to soil of shoots obtained from mother trees. Whereas shoots originated from juvenile explants rooted as high as 97%, those from adult explants showed 62% rooting. Similar result was also observed in soil acclimatization. The plantlets derived from juvenile plants survived 67%, while only 48% of those from adult trees survived. The results showed a possibility of the micropropagation of Corylopsis coreana through shoot formation from axillary buds. In addition, the advance of the research still remain to enhance the frequency of acclimatization of plantlets from mature trees for practical application.