• 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.

• Journal of Plant Biotechnology
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• v.35 no.2
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• pp.127-132
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• 2008

In bioreactor cultures of plants, inoculum density is an important factor affecting growth and proliferation of the plantlets. To maximize shoot growth and proliferation of grape rootstock '5BB' in bioreactors, inoculum density varied at 15, 30, 45 and 60 single nodes in a 3-liter scale balloon type bioreactor, respectively and cultured for 40 days. Results suggested that the growth and the photosynthesis of the plantlet were greatly affected by inoculum density in the bioreactor. The inoculum density of 45 nodes resulted in the greatest growth (910.4 mg/shoot FW, 764.4 mg/root FW) followed by 30 nodes. $CO_2$ assimilation rate, stomatal conductance, transpiration rate of the plantlet were also highest at the inoculum density of 45 nodes. Significant reduces in shoot and root growth (426.5 mg/shoot FW, 248.4 mg/root FW) were observed at the inoculum density of 60 nodes. When the inoculum density decreased by 15 nodes, plantlets were malformed due to hyperhydricity, resulting in the highest transpiration rate and the lowest $CO_2$ assimilation rate. The plantlets stressed by the inoculum density at 15 nodes and 60 nodes showed larger number and irregular shape of stomata compared to the plantlets inoculated with 45 nodes.

• Journal of Plant Biotechnology
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• v.36 no.1
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• pp.13-17
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• 2009

Various plant growth regulators were tested for shoot proliferation of Tripterospermum japonicum, a rare and endangered species. Among the six different media tested, MS medium was the best for the shoot growth. Whereas BA, upto 3 mg/L, significantly increased shoot proliferation rate, it suppressed the rate at higher levels. Neither kinetin nor TDZ was so effective in proliferating shoots as BA. As for rooting, TDZ strongly inhibited it even at very low concentration though spontaneous rooting was frequently observed from the proliferated shoots during culture of lower concentration BA or kinetin. In contrast, shoot elongation was significantly promoted by $GA_3$. More than 90% of the proliferated plantlets could be transplanted via cuttings into pots containing artificial soil mixture where they rooted and resumed normal growth. Most of the plants bloomed to bear fruits in the following year.

• Journal of Plant Biotechnology
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• v.31 no.2
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• pp.127-132
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• 2004

A suitable bioreactor culture system for shoot proliferation and bulblet formation of Allium victorialis var. platyphyllum Makino was established. Uptake of soluble carbohydrates in different bioreactor culture systems was also analyzed during the entire culture period. Optimal conditions for multiple shoot formation were determined in raft culture (RC) and modified raft culture system (MRC) (13-15 per explant) in which the explants were placed on a net contacting liquid medium. For bulblet formation and enlargement, 93.4％ of shoot clumps formed bulblets at the basal part. Furthermore, they were uniform in size when cultured with ebb & flood system (E&FS). Bulblets harvested from RC and MRC showed vigorous rooting, however, their growth was not uniform. Whereas soluble carbohydrate contents in the bulblets cultured in E&FS were low, starch content was high. Sucrose, glucose and fructose concentrations in the medium of E&FS culture system decreased as bulblet formation and enlargement proceeded, suggesting that external sucrose is taken up to by the cells before it is hydrolyzed.

• Journal of Korean Society of Forest Science
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• v.86 no.4
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• pp.430-434
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• 1997

Axillary bud explants from 3-year-old seedlings of Forsythia saxatilis N., rare and endangered species in Korea, were cultured on Murashige and Skoog's medium. The effect of various cytokinins(BAP, kinetin, and zeatin) at the different concentration(0.2, 0.5 and 1.0mg/L) was tested. Although an apparent shoot proliferation was not observed, zeatin showed slight promotional effect on normal shoot and leaf development. Both shoots and adventive roots could be induced simultaneously when the explants were cultured on the medium with kinetin, but adventive rooting was gradually reduced according as BAP and zeatin concentrations increased. Axillary shoot growth was promoted by the etiolation treatment. Shoot proliferation has been maintained more than three years with consecutive subculture. Rooted plantlets were successfully acclimatized in the artificial soil mixture and showed normal growth after transplantation into field.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.49-53
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• 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
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• v.31 no.1
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• pp.61-65
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• 2004

In order to micropropagate uniform plantlets of Alocasia cadieri Chantrier in vitro, the shoot tips were cultured on media containing various concentrations of BA and thidiazuron (TDZ). Multiple shoot formation from shoot tips was very effective on medium containing 0.1mg/L TDZ. The formed shoots from shoot tips were separated into a shoot, and cultured on media with BA, TDZ, and NM combination for proliferation. The shoots were multiplied very vigorously on medium with 0.5mg/L TDZ and 0.5mg/L NAA. The rooting and growth of multiplied shoots were more effective on medium with 2.0g/L activated charcoal, rather than those with IBA and NAA. Rooted plantlets show high survival in soil mixed with perlite 1: vermiculite 1 or vermiculite alone.

• 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.

• Journal of Plant Biotechnology
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• v.30 no.4
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• pp.375-380
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• 2003

This study was conducted to establish a practical masspropagation system of Phalaenopsis clones from basal shoot segments. The frequency of PLB (protocorm like body) induction was compared with various explants. Basal shoot segments showed the most successful result of 45％, while root tips, stalk node segments, stalk leaves and mature leaves represented low frequency (below 5％). The PLB induction ratio in the culture of basal shoot segments was examined with 11 different Phalaenopsis varieties, and the majority of varieties, including pink flower lines, showed an about 30％ rate of PLB formation. Especially, when whole basal shoot parts without cutting were inoculated onto PLB induction medium, giant PLB was induced from explant. This giant PLB was green color and big in size compared with normal PLB. When dissected giant PLB segments inoculated onto PLB multiplication medium, only normal size of PLBs were induced from them. PLBs induced by basal shoot culture were transferred onto proliferation medium and then shooting medium, from which normal plants were formed. Therefore, this culture method is considered as effective and practical protocol for Phalaenopsis mericlone production. In addition, it is suggested that clones of an infinite number can be produced consecutively by this culture system through repeated cycles of PLB induction and proliferation using the basal shoot segment of flask plant.

• FLOWER RESEARCH JOURNAL
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• v.17 no.1
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• pp.23-28
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• 2009

This study was conducted to examine the effect of plant growth regulators on the formation of adventitious bud callus(ABC) and plant regeneration in shoot tip culture of Zantedeschia spp. 'Florex Gold'. Treatment of $0.1mgL^{-1}\;N$-phenyl-N'-1,2,3-thiadiazol-5-ylurea(thidiazuron, TDZ) was more promotive for formation of ABC in shoot tip culture than 6-benzylaminopurine(BA) treatment, and short shoots were developed. Comparing to treatment of BA, mixing treatment of BA and 1-naphthaleneacetic acid(NAA) inhibited the formation of ABC and multiple shoot. The proliferation of ABC derived from sections(0.3 cm) of ABC produced by shoot tip culture in medium supplemented with $0.1mgL^{-1}\;TDZ$ was more effective in medium with $0.1mgL^{-1}\;TDZ$ or $2.0mgL^{-1}\;BA$ than the other treatments. The shoot regeneration and growth from sections of ABC was more promotive in treatment of $0.001mgL^{-1}\;TDZ$. Also, the root growth from sections of ABC was better in medium with $0.001mgL^{-1}\;TDZ$ or $0.2mgL^{-1}\;BA$. Consequently, in vitro mass production of Zantedeschia spp. 'Florex Gold' can be obtained via indirect organogenesis through plant regeneration and proliferation of ABC which was derived from shoot tip culture at $0.1mgL^{-1}\;TDZ$.