• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.347-351
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• 1994

To measure the time required for ginseng explants to become determined to form flower buds, we cultured zygotic embryos, seedlings, and cotyledonary nodes on MS medium supplemented with BA and GA$_3$of 5 ${\mu}$M each (flower inducing medium, FIM) for various periods and transferred to the basal medium. The explants required a minimum of 10 days on FIM to be determined. Histological observations revealed that the axillary meristem to be fated to develop into flower bud remained in a state of shoot meristem during the first 10 days of culture and differentiated into flower bud after 15 days of culture. We suggest that the in-vitro flowering system described in this study is useful in investigating (a) regulatory element(s) to cause the phase change from the vegetative to reproductive state by comparing predetermined explants with determined ones at the molecular level.

• Journal of Plant Biotechnology
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• v.6 no.2
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• pp.77-85
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• 2004

Development of efficient plant regeneration and genetic transformation protocols (using the Particle Inflow micro-projectile Gun and the shoot-tips as target tissue) of Sorghum bicolor (L.) Moench in terms of expression of the reporter gene, $\beta$-glucuronidase(uidA) is reported here. Two Indian cultivars of sorghum were used in the study, viz. M-35-1 and CSV-15. Plant regeneration was achieved from one-week-old seedling shoot-tip explants via multiple-shoot-clumps and also somatic embryos. The multiple-shoot-clumps were produced on MS medium containing BA (0.5, 1.0 or 2.0 mg/$L^{-1}$), with biweekly subculture. Somatic embryos were directly produced on the enlarged dome shaped expansive structures that developed from shoot-tip explants (without any callus formation) when cultured on MS medium supplemented both with BA (0.5, 1.0 or 2.0 mg/$L^{-1}$) and 2,4-D (0.5 mg/$L^{-1}$). Whereas each multiple-shoot-clump was capable of regenerating more than 80 shoots via an intensive differentiation of both axillary and adventitious shoot buds, the somatic embryos were capable of 90% germination, plant conversion and regeneration. The regenerated shoots could be efficiently rooted on MS medium containing 1.0mg/$L^{-1}$ IBA and successfully transplanted to the glasshouse and grown to maturity with a survival rate of 92%. The plant regeneration efficiency of both the genotypes were similar. After the micro-projectile bombardment, expression of uidA gene was determined by scoring blue transformed cell sectors in the bombarded tissue by an in situ enzyme assay. The optimal conditions comprising a helium pressure of 2200 K Pa, the target distance of 11 cm with helium inlet fully opened and the use of osmoticum have been defined to aid our future strategies of genetic engineering in sorghum with genes for tolerance to biotic and abiotic stresses.

• Journal of Plant Biotechnology
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• v.30 no.3
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• pp.263-267
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• 2003

This study was conducted to evaluate the effect of thidazuron(TDZ) on shoot proliferation and growth from axillary buds of 20-years-old Corylopsis coreana. Shoots proliferation was effectively achieved on WPM(Woody Plant Medium) supplemented with 0.03∼0.1mg/L TDZ. The highest shoot number(6.5$\pm$0.7) was obtained on 0.1mg/L TDZ treatment. On the TDZ medium shoots formed as clusters less than 1cm in height and therefore needed to subculture on GA$_{3}$ containing medium to induce elongation. In consecutive cultures, phenolic compounds were excreted at the proximal part of the explants and inhibited growth of the explants. Growth inhibition by the compounds was overcome using liquid and paper bridge culture system. About 60％ of the elongated shoots rooted on half- strength MS medium containing IBA. Generally, IBA was mire effective on in vitro rooting than NAA with optimal range of 0.5mg/L to 1.0mg/L. Rooted plantlets were transferred in an artificial soil(vermculite) and acclimatized in high humidity greenhouse condition. Survival rate differed greatly depending on rooting types of the explants. Two types of rooting were observed. The first type was direct rooting from the explants. The second type was callus formation followed by rooting from the callus. The explants showing the 1st type rooting survived can be multiplicated in vitro by TDZ treatment followed by elongation with GA$_{3}$ and rooting with IBA.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.4
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• pp.62-66
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• 1979

These studies were designed to define the effects of Benzyladenine and 2, 4-D on the induction and growth of callus tissue from embryos and plant segments of Korean ginseng. 0.5PPM was the minimum concentration of 2, 4-D for the induction of callus tissue from embryos and plant segments of ginseng. Best callus induction occurred at a 2, 4-D concentration of 5 mg/liter but growth of this callus was best at a 2, 4-D concentration of about 1.0 to 2.0 mg/liter and benzyladenine was ineffective as callus inducer. When the embryos were grown on the media containing 0.5 mg/liter of 2, 4-D, 5 to 6 axillary buds were formed at the basal part of epicotyle.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.716-722
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• 2006

Various light sources including LEDs (Light emitting diodes) affecting on shoot growth was examined using in vitro shoots of E. pellita. Generally, it appeared that ventilation treatment was the most important factor affecting on normal shoot growth, irrespective of irradiation sources. Ventilation resulted in better performance of the cultures under 100% blue LED radiation. These include better shoot growth, more number of leaves, more number of internodes, more number of axillary buds, and heavier dry matters. The highest total chlorophyll content was obtained under both cool-white fluorescent lamps and R5B5 (50% red LED + 50% blue LED). The value was $24.5{\mu}g/g$ and $20.1{\mu}g/g$, respectively. In addition, ventilation resulted in higher carotenoid content in all irradiation sources except 100% red LED radiation. In conclusion, shoot growth of E. pellita could be reached maximum by ventilation under R5B5 (50% red LED + 50% blue LED).

• Korean Journal of Plant Resources
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• v.28 no.6
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• pp.690-696
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• 2015

We micropropagated pear (Pyrus species) using shoot tips and nodal explants from three pear genotypes. The ability to establish shoot tip cultures, proliferate shoots, induce rooting, and acclimatize the resulting plantlets are all elements of in vitro micropropagation. Shoots were induced from shoot tips on Murashige and Skoog medium (MS) with five different plant growth regulator combinations. The highest shoot formation rates were achieved for the three genotypes using MS supplemented with 1.0 mg/L N⁶-benzyladenine (BA) and 0.1 mg/L gibberellic acid (GA₃). The maximum shoot number and shoot length for the three cultivars were recorded with 2.0 mg/L BA and 0.2 mg/L indole-3-butyric acid (IBA) in multiplication medium using nodal explants produced from microshoots. Nodal explants with one or two axillary buds cultured for three weeks initiated roots on medium supplemented with various concentrations of 1-naphthaleneacetic acid (NAA) or/and IBA in half-strength MS medium for adventitious rooting. The highest rooting response was with the combination of 0.2 mg/L NAA and 0.2 mg/L IBA. A combination of NAA and IBA resulted in a significant increase in the rooting ratio over NAA or IBA alone. In this medium, the root formation rate according to ranged from 68.9% for the BaeYun No. 3 genotype to 51.8% for the Hwanggeum genotype. We also investigated the influence of the concentration the polyamine phloroglucinol in rooting medium. For all three genotypes, the highest rooting ratio, longest root length, and greatest root number were observed in the treatments with 75-150 mg/L phloroglucinol. Most rooted plants were acclimatized successfully.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.343-356
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• 2010

Plant micropropagation techniques include bud cultures using apical or axillary buds, organogenesis through callus culture or adventitious bud induction, and somatic embryogenesis. In Korea Forest Research Institute (KFRI), the first tissue culture trial in woody plant was initiated from the bud culture of hybrid poplars (Populus alba x P. glandulosa) in 1978. Since then several mass propagation techniques have developed from conifer and hardwood species, resulting in allowing practical application to Poplars, Birches and some oak species. In addition, useful micropropagation and genetic resources conservation techniques were established in some rare and endangered tree species including Abeliophyllum distichum. Among various in vitro propagation techniques, somatic embryogenesis is known to be the most efficient plant regeneration system. Since the first somatic embryo induction was reported in Tilia amurensis by KFRI in 1986, various protocols for direct or indirect somatic embryogenesis systems have developed in conifer and hardwood species including Larix leptolepis, Pinus rigida x P. taeda F1, Kalopanax septemlobus and Liliodendron tulipifera, etc. However, most of these technologies have been developed using juvenile tissues, i.e. immature zygotic embryos or mature embryos. Therefore it has been difficult to directly application to tree breeding program due to their unproven genetic background. Recently remarkable progresses and new approaches have been achieved in mature tree somatic embryogenesis. In this article we reviewed several micropropagation techniques, which have been mainly developed by KFRI and recent international progresses.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.23-23
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• 2021

Apple (Malus×domestica Borkh.; Rosaceae) is an important fruit crop grown mainly in temperate regions of the world. Tissue culture in vitro is a biotechnological technique that has been used to genetically improve cultivars (scions) and rootstocks. This could be important in the production of genetically uniform scions and rootstocks for commercial apple production. In nurseries, apple plants are produced by grafting scions onto rootstocks. The Cornell-Geneva (Geneva® series) breeding program has bred several dwarf rootstocks that are resistant to diseases and pests and are also cold hardy. This study was conducted to determine the optimal medium strength to improve sprouting shoot rate of apical meristem of the apple rootstocks of fire blight resistance. The apple rootstocks apical meristem at size (0.2 mm to 0.3 mm) with axillary buds were cultured on the MS(Murashige & Skoog) medium supplemented with plant growth regulators. The sprouting ratio and growth characteristics was evaluated after eight weeks in vitro culture. The highest rate of bud differentiation and shoot formation were 23.8% and 55.6%, respectively. After 6 weeks, shoots were regenerated from apical meristem, and their growth characteristics was significantly varied on the respective basal medium with different plant growth regulators. Our studies showed that the apple rootstocks the apple rootstocks of fire blight resistance plantlets could be successfully produced from apical meristem differentiated out of young twigs via organogenic regeneration.

• Horticultural Science & Technology
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• v.18 no.6
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• pp.834-838
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• 2000

As an endeavor to establish a micropropagation system for Epimedium koreanum Nakai., this study was carried out to define methods to disinfect its explants and media for callus induction, proliferation and plant regeneration. The lowest infection rates by fungi or bacteria on apical and axillary bud explants of rhizome were observed when they were immerged in 0.3% NaOCl solution for 20 min after soaked in 0.1% $AgNO_3$ solution for 30 min, but leaf explants were seldom infected with fungi or bacteria by this disinfectant method. The highest rate of plantlet formation was obtained from the explants disinfected in 0.3% NaOCl solution for 20 min after soaked in 0.1% $AgNO_3$ solution for 60 min for tip buds and in 0.1 % $AgNO_3$ solution for 30 min for axillary buds of rhizome. Induction rate of callus was the highest from the explants disinfectd in 0.3% NaOCl solution for 20 min after soaked in 0.2% $AgNO_3$ solution for 15 min. Callus growth was proper in a modified 1/2 MS medium including half strength of $NH_4NO_3$ with $0.02-0.2mg{\cdot}L^{-1}$ BA and $2.0mg{\cdot}L^{-1}$ NAA. Low rate of plantlet regeneration was obtained in 1/2 UM or 1/2 White medium with $2.0mg{\cdot}L^{-1}$ BA and $0.2mg{\cdot}L^{-1}$ AA.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.3
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• pp.226-234
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• 1984

In order ti find out the optimum seeding time(OST) and optimum seed rate(OSR) of Italian ryegrass on seed production, this studies with tetraploid cv. Tetrone were carried out on the experimental field of Livestock Experiment Station. Treatments included seed rates of 1, 2, 3 and 4 kg per 10a and combined with seeding time on 20, 30 Aug, 9, 19 and 29, September 1983. Seeds were sown in rows 50 cm apart and were spaced in a continuous line with width of 15 cm within the rows. The results are summarized as follows: 1. Autumn tillers could be classified into three groups from winter-killing point of view, namely winter-killing completely, damaged growing point only and living tillers. 2. The young inflorescence-bearing stem in Italian ryegrass which were sown earlier than 9. September were more susceptible to winter killing. Tiller buds in those stems which originated from an axillary buds at the stem base within senescent leaf-sheaths emerged lately in spring, and consequently heading was delayed, culm length shortened and seed yield reduced. 3. Tiller buds which originated from damaged growing point only and living tillers in moderate shoots emerged early in spring and those tillers became mainly spike-bearing culm. 4. The emergence-time of tillers influenced on culm-, spike- length and ripenness more than seeding time and seed rate. 5. Seed yield was mostly affected by the number of spikes per unit area. 6. For the safety of over-wintering and enough spikes on seed production, OST and OSR at Suweon were the last part of September and 2-3 kg per 10a, respectively. Especially OSR was 2 kg per 10a for early and 3 kg per 10a for late OST.