• Horticultural Science & Technology
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• v.17 no.6
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• pp.742-746
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• 1999

Contents of mineral element and cytokinin in the xylem sap of 'Keumdongee' and 'Tongilhwang' oriental melons were compared with those in oriental melons grafted onto 8 rootstocks. The effect of grafting on the fruit quality of oriental melon was also investigated. Flesh firmness varied with rootstocks. Soluble solids contents in the placenta tissue of grafted 'Tongilhwang' were higher than that in the 'Keumdongee'. Electric conductivity of the xylem sap in own-rooted plants was higher in 'Keumdongee' than in 'Tongilhwang', but it increased in 'Tongilhwang' once they were grafted. The sap volume per plant was greater in 'Keumdongee' than in 'Tongilhwang'. The mineral concentrations varied considerably depending on the rootstock used. Xylem sap of grafted oriental melons contained a higher amount of mineral ions, especially $NO_3{^-}$ and $PO_4{^-}$, than did the sap in own-rooted plants. The increase in the mineral levels in sap due to grafting was most apparent in 'Tongilhwang'. Xylem sap from both 'Keumdongee' and 'Tongilhwang' contained trans-zeatin (t-Z), trans-zeatin riboside (t-ZR), and dihydrozeatin riboside (DHZR). Small amounts of isopentenyl adenine (IPA) and isopentenyl adenine riboside (IPAR) were also detected. Trans-zeatin riboside was the most abundant, followed by t-Z. Cytokinin concentration in 'Keumdongee' was not significantly influenced by rootstock type used, although the highest concentration of cytokinins in 'Keumdongee' was obtained with 'Chamtozwa' rootstock. However, the cytokinin concentration in 'Tongilhwang' increased with grafting irrespective of rootstock type used.

• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.53-57
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• 1995

This study was carried out to investigate the effect of TDZ (thidiazuron) treatment on Propagation in vivo through scale cultures of Narcissus pseudonarcissus. Scales with disk (5 to 7 m in size) were cultured on MS medium containing NAA, BA and TDZ. Bulbs and shoots were directly formed when scales were cultured on medium containing 5 mg/L NAA and 1 mg/L BA. In addition, combination of 3 mg/L NAA and 0.02 mg/L TDZ promoted effectively the direct formation of bulbs and shoots. The shoots were rooted when cultured on medium containing 5 mg/L NAA and 0.02 mg/L TDZ. non scales obtained from regenerates were cultured on medium containing 1.0 mg/L NAA and 0.5 mg/L TDZ, they gave rise to numerous bulbs and shoots . The overall results suggest that TDZ is an effective plant growth regulator in vitro propagation of N. pseudonarcissus.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.105-110
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• 2002

Effects of difference between day and night temperatures (DIF) and cytokinins on in vitro growth of 'Campbell Early' grape plantlets were investigated, Shoot growth was suppressed by -7DIF (18/$25^{\circ}C$). Effects of BA and TDZ were not affected by DIF. 0DIF (25/$25^{\circ}C$) enhanced the growth with increasing cytokinin level. Kinetin at 10 $\mu$M was the most effective for shoot growth with 87 mm among cytokinins used except for control. Zeatin and kinetin each at 5 $\mu$M significantly increased shoot growth to respective 162 and 110 mm. In 0DIF, two-fold increase of 162 mm was obtained by 5 $\mu$M zeatin. In control, no further shoot proliferation was observed regardless of DIF. In 0 and ＋7DIF (25/18$^{\circ}C$), 4 shoots were observed with 10 $\mu$M BA. Zeatin, 2iP and kinetin resulted in poor shoot proliferation while BA at 10 $\mu$M resulted in profuse branching in all DIFs.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.259-264
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• 2006

This experiment was conducted to investigate the effects of medium composition, physical condition and growth regulators on prothallus proliferation in 3 fern species belonging to Aspleniaceae (Asplenium incisum, Camptosorus sibiricus and Phyllitis scolopendrium). In all of the 3 species, the effective medium for prothallus proliferation was Murashige and Skoog's basal medium with 1% sucrose and pH 5.8. The optimum $NH_4^+:NO_3^-$ concentration ratio of protahllus proliferation was 20:40mM (1:2 ratio) in A. incisum and P. scolopendrium and 30:30mM (1:1 ratio) in C. sibiricus. However, agar content of medium did not affect the rate of prothallus proliferation. Among the selected 6 kinds of growth regulators (NAA, IAA, 2,4-D, BAP, kinetin and lip), cytokinins generally has a promotive effect, but auxins showed an inhibitory effect on prothallus growth.

• Korean Journal of Plant Resources
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• v.19 no.4
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• pp.524-529
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• 2006

In vitro culture system was established to induce multiple shoots of Albizzia julibrissin Duraz. by investigating the effects of cytokinins. Cotyledon, hypocotyl and root explants were cultured on MS media supplemented with either three different plant growth regulators or their combinations. The most effective cytokinin sources were zeatin 2.0 + TDZ 0.5 mg/L in cotyledon, zeatin 1.0 mg/L in hypocotyl, and BA 0.2 + TDZ 0.01 mg/L in root explant for producing shoots ($5.67\;{\pm}\;1.20$, $19.50\;{\pm}\;3.50$, and $20.50\;{\pm}\;2.47$, respectively). Also, zeatin treatment was tended to induce more shoots rather than the combinations of other cytokinins. In addition, the root induced in 1/2 MS medium without any plant growth regulators was longer and thicker than treatments of IBA, NAA, IAA and 2.4-D as auxins. Overall, the highest average percent of in vitro shoot formation was 73% from three different types of explants with treatment of zeatin (1.0mg/L).

• Horticultural Science & Technology
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• v.19 no.1
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• pp.34-38
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• 2001

This experiment was conducted to find out the optimum cultural conditions for the propagation of M.9 apple rootstocks such as EMLA M.9 and NAKB T-337 in vitro. Murashige and Skoog (MS) medium supplemented with $1.0mg{\cdot}L^{-1}$ BA, $0.1mg{\cdot}L^{-1}$ IAA, $30g{\cdot}L^{-1}$ sucrose, and $8g{\cdot}L^{-1}$ agar was suitable for shoot proliferation. Removing of apical meristem and horizontal placing of explants on medium increased shoot proliferation significantly. The best rooting was obtained on 1/2 MS medium supplemented with 0$0.5mg{\cdot}L^{-1}$ IBA, $20g{\cdot}L^{-1}$ sucrose, and $8g{\cdot}L^{-1}$ agar.

• Korean Journal of Agricultural Science
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• v.30 no.2
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• pp.115-122
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• 2003

This experiment was conducted to find the effect of a non-purine cytokinin, thidiazuron(TDZ), on the increase of berry size and fruit quality in 'Kyoho' grapes. For the comparison, the effect of forchlorfenuron(CPPU) was also examined The number of shot berries per cluster was significantly increased by the application of TDZ at 5 days after calyptra fall, resulting in the increase of cluster weight but no increase of each berry weight. The increase of berry weight was found when TDZ was applied at 10 to 15 days after calyptra fall. Gibberellin(GA $25mg{\cdot}L^{-1}$) was also effective on the increase of berry weight and the combined application of GA and TDZ further increased the berry weight. TDZ showed stronger effect on the increase of berry weight than CPPU at the same concentration. Berry ripening was more delayed at higher concentration of TDZ but no chemical injury was observed even at $20mg{\cdot}L^{-1}$. Results indicated that TDZ was effective on the quality improvement through berry weight increase and the recommended concentration TDZ for 'Kyoho' grapes was 5 to $10mg{\cdot}L^{-1}$.

• Korean Journal of Plant Tissue Culture
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• v.21 no.4
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• pp.239-246
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• 1994

The genotypic (2n, 3n, 4n) response of watermelon in vitro shoot tip culture was evaluated. Different genotypes had similar response in terms of shoot formation and growth. Shoot formation was better at lower concentration of 0.3 mg/L BA and higher concentration of 5-10.0 mg/L 2iP and kinetin, but growth of newly formed shoot was inhibited. With further subculture, kinetin did not promote shoot formation Better shoot formation was observed at 0.3-0.5 mg/L BA. Combination of 0.3 mg/L BA and 0.3-0.5 mg/L BA was effective in shoot multiplication, growth and induction of more internodes. Varrying levels of light intensity and agar concentration did not affect the performance of tetraploid plants. Higher light intensity and agar concentrations decreased the number of shoot formed in triploid plane. Growth in both genotype, however was inhibited. Higher light intensity was found to promote leaf senescence in all genotypes. All growth inhibitors decreased the number of shoots formed and slowed plant growth there by prolonging duration of cultures. Growth inhibitors were to observed to decrease incidence of hyperhydricity in culture. No difference in shoot formation was observed in each of the concentrations used in Ancymidol, TIBA, CCC and PP333. Shoot formation and growth was more inhibited in ABA treatments. Leaf expansion and growth was poor in all treatments.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.46-50
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• 2013

Some rhizobacteria producing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase can make plant to continue growth under the stress conditions through lowering the level of phytohormone, ethylene which inhibits the plant growth and accelerates plant aging. In this study, some rhizobacteria producing ACC deaminase have been isolated from the rhizosphere of plants grown at sand beaches, and identified as Escherichia hermannii m-2, Enterobacter asburiae m-4, Pseudomonas thivervalensis BD2-26 and Pseudomonas brassicacearum subsp. neoaurantiaca BD3-35 through sequencing of 16S rRNA genes. Strain BD3-35 showed the highest activity of ACC deaminase among the isolates, 20.26 ${\alpha}$-ketobutyrate ${\mu}M/mg$ protein/h. Strains BD3-35 and BD2-26 secreted a phytohormone cytokinin, and strains m-4 and m-2 could produce auxin and abscisic acid, respectively. When these bacteria were applied to the 7-day old tomato plant under drought stress for 7 days, strains BD3-35, m-2, and m-4 increased the length of tomato root by 14, 15, and 35%, respectively, and strains m-2, BD2-26 and BD3-35 increased the dry weight of tomato plant by 22, 33, and 68%, respectively compared to the uninoculated control tomatoes. Therefore, these rhizobacteria may be utilized as a microbial fertilizer for the plants under drought stress.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.123-127
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• 2002

Effect of cytokinins (BA, TDZ, zeatin, 2iP, and kinetin) applied either singly or in combination on in vitro growth of two grape cultivars ('Cabernet Sauvignon' and 'Campbell Early') was investigated as a serial work for mass production of grapevine nursery stocks. In single treatment, shoot growth of two cultivars was most favorable in control. Shoot proliferation was satisfactory with 10 $\mu$M BA regardless of cultivars and cytokinin combinations, followed by TDZ. Other treatments resulted in very poor or no branching. Total explants ready for subculture produced by 10 $\mu$M BA outnumbered those by other treatments. TDZ was also effective. TDZ significantly increased the fresh weight and callus formation while shoot growth was unsatisfactory. Shoot growth response of two cultivars in combined treatments was also most favorable in control as was in single treatments. When TDZ was combined with zeatin, 2iP, and kinetin which failed to induce branching, proliferous branching was induced though the shoot number was behind that of single treatments of BA and TDZ. TDZ was very effective for total number of explants and fresh weight, showing 10-fold increase.