• Journal of Plant Biotechnology
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• v.48 no.1
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• pp.54-61
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• 2021

This work describe an efficient method for the shoot induction and plant regeneration of seedling-derived apical bud explants of Tilia mandshurica Rupr. & Maxim. The highest rate of shoot induction (82.2%) was obtained when apical bud explants from juvenile seedlings (5 months old) were cultured on Murashige and Skoog (MS) medium containing 1.0 mg/L 6-benzylaminopurine (BAP). However, apical bud explants obtained from mature trees (12 years old) did not produce any shoots, even with BAP supplementation. Among the three cytokinins tested for shoot multiplication (BAP, zeatin, and kinetin), BAP was the most effective; the highest number of shoots per explant (2.1) was observed on MS medium supplemented with 1.0 mg/L BAP. In contrast, the longest average shoot length (3.0 cm) was observed after growth on MS medium with 2.0 mg/L zeatin. No multiplication occurred when apical bud explants were cultured with kinetin-supplemented media. During rooting of in vitro-elongated shoots, the highest rooting rate (100%) was observed in half-strength MS medium supplemented with 0.5 ~ 1.0 mg/L indole-3-butyric acid (IBA) or 3.0 mg/L 1-naphthaleneacetic acid (NAA). During the acclimatization process, plantlets that were rooted on the IBA (0.5 mg/L)-supplemented medium had the highest survival rate (100%) and maximum root length (18.5 cm). These findings suggest that a low concentration (0.5 mg/L) of IBA is appropriate for the rooting and acclimatization of T. mandshurica. Plants were successfully transferred to the greenhouse with a 100% survival rate. This protocol will be useful for the large-scale propagation of Tilia species.

• Journal of Plant Biotechnology
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• v.49 no.2
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• pp.124-130
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• 2022

The application of traditional taro propagation methods for large-scale cultivation would be insufficient to meet the high demand for quality planting materials. Therefore, this study aimed to develop an in vitro micro-propagation technique for two local taro cultivars (cv.), Wangi and Putih. Taro cormels were collected from the Malaysian Agricultural Research and Development Institute (MARDI) germplasm (Serdang, Malaysia). Explants were taken from the shoot tip of cormels and initially cultured on Murashige and Skoog (MS) basal media for four weeks. The explants were then transferred to different multiplication media supplemented with different types and concentrations of cytokinins such as 6-benzylaminopurine (BAP ) and Thidiazuron (TDZ). Shoot production was quantified after six weeks of culture. The highest mean number of new shoots was produced by the Wangi cultivar on MS medium supplemented with 2.0 mg/l BAP (2.10 shoots), MS medium supplemented with 0.5 mg/l TDZ (2.18 shoots), and Gamborg B5 medium supplemented with 6.0 mg/l BAP (2.43 shoots). The maximum average number of the Putih cultivar shoots was obtained on MS supplemented with 2.0 mg/l BAP (3.57 shoots). MS basal media was used for root initiation, as it produced an average of 25 roots with an 11-cm length. Various types of substrate mixtures were used during acclimatization. The best acclimatization substrate for the Wangi cultivar was 100% peat soil, whereas the Putih cultivar grew optimally in a combination of peat and perlites at a 1:1 ratio. Taro plantlets require approximately 4 to 6 weeks to acclimatize before they can be transferred to the field.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.331-338
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• 2022

Sunflower (Helianthus annuus L.) protoplasts were isolated from seven-day-old etiolated hypocotyls of 10 A line and four-week-old fully expanded young leaves of PI 441983 line in vitro seedlings using an enzymatic method. Purified protoplasts were collected by filtration and floatation in sucrose solution. Semi-solid protoplast culture was performed using the L4 regeneration protocol with various culture media and plating densities to achieve the highest efficiencies for protoplast culture of hypocotyl and mesophyll protoplasts of 10 A and PI 441983 lines, respectively. The concentrations in liquid L'4M medium and different plating densities were evaluated in two types of cytokinins, the adenine-type 6-benzyladenine (BA) and the phenylurea-type thidiazuron (TDZ). The highest colony formation was achieved in both sunflower lines when 0.5 mgL^-1 BA and 0.5 mgL^-1 TDZ were applied with a high plating density (3 × 10⁵ protoplasts mL^-1). These conditions led to 38.45% and 39.40% colony formation for hypocotyl protoplasts of the 10 A line and mesophyll protoplasts of the PI 441983 line, respectively. Moreover, many hypocotyl protoplast-derived colonies developed into micro-calli. In addition, superior development of both sunflower protoplasts was observed with all plating densities when BA was used in combination with TDZ. This finding will be applicable to future sunflower hybrid production via somatic hybridization.

• Journal of Korean Society of Forest Science
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• v.82 no.3
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• pp.221-226
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• 1993

Methods for shoot proliferation via pulse treatment onto the microshoots of Quercus acutissima, and ex vitro root induction using peat plug systems of the microshoots of 4 oak trees were described. Pulsing solution was prepared by the addition of BA and/or BA plus zeatin onto the aqueous WPM and sterilized distilled water. Using the solution, pulsing time was adjusted at different levels(0. 1, 2, 5. 9, and 24 hours). Although the effect of pulsing solution prepared by the addition of cytokinins onto the sterilized distilled water was slightly lower in shoot proliferation rate, a little higher in shoot elongation was observed compared with that of aqueous WPM. One hour of pulse treatment revealed best in shoot proliferation and its elongation, whereas the increment of pulsing time slightly suppressed the response. In addition, prolonged pulse time resulted high frequency of hyperhydric shoot appearance. Single treatment of BA was better in shoot proliferation than that of BA combination with zeatin, whereas the latter treatment usually showed rapid and healthy shoot growth. For ex vitro root induction using peat plug systems, black oaks(Q. acutissima and Q. variabilis) revealed excellent rootability compared with white oaks(Q. serrata and Q. mongolica). Shoot-tip necrosis of white oaks eras one of the big problems for survival. In this study, we discribed the effect of pulse treatment, successful ex vitro rooting system by the incorporation of peat plug, and the possibilities for the overcoming the obstacles on micropropagation of oaks.

• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.376-379
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• 2015

This study was conducted to evaluate the effects of different types and concentrations of organic nitrogen sources (${\small{L}}$-Glutamine and casein hydrolysate, CH) and plant growth regulators (auxins and cytokinins) on embryogenic tissue proliferation and somatic embryo production in L. kaempferi. Overall, the highest tissue fresh weight was obtained at either 2 or 4 weeks in culture when 1,000 mg/L ${\small{L}}$-Glutamine was added to the culture medium, which showed similar results with other treatments. In experiments with different types and concentrations of plant growth regulators on somatic embryo production, the highest production (426.3/90 mg tissue) was found when 0.2 mg/L IBA was added; however, no somatic embryos were induced following treatment with 0.2 mg/L BA or Kinetin. The effect of various concentrations of IBA on somatic embryo production was also tested. The best result (303/90 mg tissue) was obtained when plants were treated with 0.2 mg/L IBA; 1.0 mg/L IBA was also effective (281/90 mg tissue). The lowest result (109.3/90 mg tissue) was obtained with 5.0 mg/L IBA.

• Korean Journal of Medicinal Crop Science
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• v.12 no.6
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• pp.500-507
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• 2004

The establishment of an efficient protocol of plant regeneration from leaf explant cultures of Perilla spp. is reported. Regenerated shoots were obtained from leaf explant cultures on solid MS medium containing different concentrations of cytokinins and auxin. The effect of cytokonin and auxin differed depending on each acession. The combination treatments of high level of cytokinin and low level of auxin was more effective for plant regeneration in Perilla frutescens. The best concentration of sucrose was 3% for regeneration. Of spermidine, spermin and putrescine. treatments, the most effective treatment for plant regeneration was $10\;mg/{\ell}$ spermidine.

• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.251-256
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• 2005

Cytokinins are essential plant hormones that play crucial roles in various aspects of plant growth and development. To better understand the molecular mechanisms of cytokinin action, we identified cytokinin related proteins by a proteomic approach. Proteins extracted from control and trans-zeatin treated Arabidopsis seedlings were separated and analyzed by two dimensional gel analysis. Differentially expressed protein spots were identified with peptide mass fingerprinting based on matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and database searching, We obtained ten up-regulated and one down-regulated proteins upon t-zeatin treatment. The expression of the following proteins was induced; pollen allergen like protein, L-ascorbate peroxidase, tetrapyrrole methylase family protein, SGT1 protein homolog, disease resistance related protein, maternal embryogenesis control protein, paxneb related protein, gluthathione S-transferase and IAA amino acid hydrolase homolog.

• 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.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.678-684
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• 2010

In an attempt to improve biomass and bioactive compound production, we cultured adventitious roots of $Eleutherococcus$ $koreanum$ in 250 mL Erlenmeyer flasks using Murashige and Skoog (MS) medium with different concentrations of auxins (IBA, NAA, IAA) and cytokinins (BA, kinetin, TDZ). Root biomass (fresh and dry weight) was enhanced at $5mg{\cdot}L^{-1}$ indole-3-butyric acid (IBA) after 5 weeks of culture. The content of total phenolics and flavonoids was also increased with $5mg{\cdot}L^{-1}$ IBA compared to ${\alpha}$-naphtalene acetic acid (NAA) or indole-3-acetic acid (IAA) treatments. The combination of $5mg{\cdot}L^{-1}$ IBA with $0.1mg{\cdot}L^{-1}$ thidiazuron (TDZ; N-phenyl-N'-1,2,3,-thidiazol-5-ylurea) enhanced root fresh and dry weight (1.4- and 1.6-fold, respectively) as well as the content of total phenolics and flavonoids compared to the relative control (without cytokinin). On the contrary, $N_6$-benzyladenine (BA) and 6-furfurylaminopurine (kinetin) did not significantly affect root biomass and bioactive compound production in adventitious roots of $E.$ $koreanum$. These results suggested that $5mg{\cdot}L^{-1}$ IBA combination with $0.1mg{\cdot}L^{-1}$ TDZ supplementation was most suitable for both biomass and bioactive compound production from adventitious roots of $E.$ $koreanum$.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.167-172
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• 2015

The aim of this study was to develop an effective production system of blueberry plants by using tissue culture technique. Murashige and skoog medium (MS) and woody plant medium (WPM) were compared for shoot formation of highbush blueberries. Also medium supplemented with zeatin/2-isopentenyl adenine (2iP)/benzyl aminopurine (BA) (1, 2/10, 15/4, $6mg{\cdot}L^{-1}$)and zeatin/2iP/BA (0.5/10, 15/$0.05mg{\cdot}L^{-1}$) as plant growth regulators to determine the effect of shoot formation and shoot proliferation, respectively. The shoot explants cultured on WPM showed higher shoot formation rates, more number of nodes, and longer root length than those on MS medium during the primary culture. Shoots were not formed when the explants were cultured on the medium without plant growth regulators or on only BA. The shoot explants cultured on the medium supplemented with 2iP showed low rates of shoot formation. On the other hand, zeatin was the most effective for shoot formation and growth of the explants. Also influence of different cytokinins (zeatin, 2iP) on the shoot proliferation of subcultured shoot explants was studied. There was no significant difference among the different concentrations of zeatin in the rate of shoot formation and number of shoots. However at higher concentration of zeatin, number of nodes was increased, and shoot length was shorted. The proper concentrations of zeatin for shoot propagation in subculture were found to be $0.5mg{\cdot}L^{-1}$ and $1mg{\cdot}L^{-1}$.