• FLOWER RESEARCH JOURNAL
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• v.17 no.2
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• pp.121-127
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• 2009

This study was conducted to improve commercial quality of a cut spray chrysanthemum 'Gama' bred in Korea by foliar application of daminozide (DMZ), suppressing excessive elongation of peduncle caused by high temperature in summer season production. Applications were made at three floral bud developmental stages (I, II, and III), and concentrations used were 0, 500, 1000, and $2000mg{\cdot}L^{-1}$. Both cut flower length and peduncle length showed the greatest suppression of elongation by DMZ treatments at stage II. DMZ also gradually reduced values of those in a concentration-dependant manner. Stem thickness and flower diameter reduced compared to control as DMZ was sprayed at later stage and those two characteristics decreased in a concentration-dependant manner. The number of paralleled flowers neighboring apical part of whole plant showed the best results at stage I and II. As for DMZ concentration, those increased effectively at $500-1,000mg{\cdot}L^{-1}$. Among all combinations, $1,000mg{\cdot}L^{-1}$ DMZ at stage II recorded the most paralleled flowers and showed 24.2% increment as compared to control. The number of fully expanded flowers and total floral buds also showed the highest values using $1,000mg{\cdot}L^{-1}$ DMZ at stage II than the other treatments. In cut spray chrysanthemum cultivar 'Gama' bred in Korea, foliar-spraying with $1,000mg{\cdot}L^{-1}$ DMZ at stage II most effectively suppressed excessive peduncle elongation, parallelled flower cluster arrangement, and increased the number of flowers in summer. However, this combination affected negatively the other commercial qualities, reducing cut flower length, stem thickness, and flower diameter. Therefore, we recommended that foliar-spraying stage and DMZ concentration was stage I and $1,000mg{\cdot}L^{-1}$, respectively, in a practical culture for 'Gama'.

• FLOWER RESEARCH JOURNAL
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• v.18 no.4
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• pp.231-237
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• 2010

This study was conducted to improve commercial quality of a cut spray chrysanthemum 'Ilweol' bred in Korea by foliar application of daminozide, suppressing excessive elongation of peduncle caused by high temperature in summer season production. Applications were made at three floral bud developmental stage (I, II, and III), and concentrations used were 0, 500, 1000, and $2000mg{\cdot}L^{-1}$. Cut flower length and peduncle length showed the greatest repression of elongation through daminozide treatments at stage III and stage II, respectively. Daminozide also gradually reduced values of those in a concentration-dependant manner. Flower diameter increased compared to control as daminozide was sprayed at later stage but decreased in daminozide concentration-dependant manner. Angle of flower cluster on apical part of whole plant showed the best results when sprayed with $2,000mg{\cdot}L^{-1}$ at stage III. Among all combinations, $2,000mg{\cdot}L^{-1}$ daminozide at stage II recorded the highest angle of flower cluster and showed 31.3% increment as compared to control. The number of fully expanded flowers showed the highest values using $2,000mg{\cdot}L^{-1}$ daminozide at stage III than the other treatments and total floral buds also showed the highest values using $2,000mg{\cdot}L^{-1}$ daminozide at stage I than the other treatments. In cut spray chrysanthemum cultivar 'Ilweol' bred in Korea, foliar-applying with $2,000mg{\cdot}L^{-1}$ at stage III most effectively suppressed excessive peduncle elongation, angle of flower cluster, and increased the number of flowers in summer. However, this combination affected negatively the other commercial qualities, reducing cut flower length and flower diameter. Therefore, we recommended that foliar application stage and daminozide concentration was stage III and $500mg{\cdot}L^{-1}$, respectively, in a practical culture and cut flower quality for 'Ilweol'.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.135-143
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• 2011

In the Doritaenopsis hybrid, like most of the orchid species and hybrids, temperature is crucial for the vegetative-to-reproductive transition, and low temperature is required for bud differentiation. To understand the molecular mechanism of this process, an orchid GIGANTEA (GI) gene, DhGI1, was isolated and characterized by using the rapid amplification of cDNA ends (RACE) PCR technique. Sequence analysis showed that the full-length cDNA is 4,022 bp with a major open reading frame of 3,483 bp, and the amino acid sequence showed high similarity to GI proteins in Zea mays, Oryza sativa, Arabidopsis thaliana and other plants. Semi-quantitative RT-PCR revealed that DhGI1 was expressed throughout development and could be detected in roots, stems, leaves, peduncles and flower buds. The expression level of DhGI1 was higher when the plants were flowering at low temperature (22/$18^{\circ}C$ day/night) than the other growth stages. Further analysis indicated that the accumulation of DhGI1 transcripts was significantly increased at low temperature, and concomitantly, initiation of the peduncle was observed. However, DhGI1 levels were low under high temperature (30/$25^{\circ}C$) conditions, and flower initiation was inhibited. These results indicate that the expression of DhGI1 is regulated by low temperature and that DhGI1 may play an important role in inflorescence initiation in this Doritaenopsis hybrid at low temperatures.

• Korean Journal of Medicinal Crop Science
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• v.4 no.3
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• pp.187-192
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• 1996

This study was investigated to know about the stages of flower bud development and the effects of natural and artificial cold treatment on flowering of herbaceous peony. Developing buds of Paeonja lactㅑflora Pall. var. Taebaek were observed since Jun. 17 and peony plants were forced since Nov. 27 in the green house with two weeks interval, and other plants were forced after cold treatment in $5^{\circ}C$ for 1, 2, 4, 6weeks. Differentiation of vegetable part in peony buds was started in early June, and floral part was differentiated in September and their differentiation was continued to shooting in early spring. Buds of peony were sprouted and flowered when it was forced on Dec. 4. Days to shooting were decreased with delay of forcing time from early to late of December, significantly. Two weeks for cold treatment were enough to break dormancy of peony and days to shooting of the cold treated were significantly shorter than the untreated in the same forcing times

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.169-174
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• 2017

BACKGROUND:Kiwifruit growers build their vineyards using many windbreaks to protect their kiwifruit vines from defoliation injury by strong winds such as typhoon. In this study, we have compared fruit quality, budbreak rate and floral bud as affected by windbreaks. And also we surveyed several microclimate indices of kiwifruit orchard depending on the covering materials of arch-type windbreaks. METHODS AND RESULTS: Five different windbreak materials including polyethylene film (PE), blue- and white-colored nets were tested in pipe-framed archtype kiwifruit vineyards as the covering materials. Photosynthetically active radiation (PAR), annual mean temperature (AMT) and chill unit (CU) as well as fruit quality were compared among the covering materials. In all treatments, annual PAR was more than $400{\mu}mol\;m^{-2}s^{-1}$, in which kiwifruit leaf could reach its maximum photosynthesis, since the leaves were emerged. Annual mean temperature was greater in 0.1 mm-PE covering as much as $1-2^{\circ}C$ than other windbreaks. In CU calculated by three different models, all windbreaks showed more than 1400 CU that is fully fulfilled CU for kiwifruit rest completion. There were no difference in budbreak rate among the covering materials. Fruit weight was heavier in 0.1 mm-PE and white-net (4 mm) than other windbreaks. CONCLUSION: Regardless of the windbreak materials, the PAR quantity was enough for kiwifruit photosynthesis. And CU for kiwifruit rest completion was fully achieved in all treatments. However, with respect to fruit weight, quantity of PAR, and AMT, etc., It is highly recommended for kiwifruit growers to choose 0.1 mm-PE and white-net (4 mm) as for their windbreaks materials.

• Journal of Plant Biotechnology
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• v.3 no.2
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• pp.89-94
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• 2001

In vitro plant regeneration of inbred breeding line of hot pepper (Capsicum annuum L.) was established using leaf and petiole segments as explants. About 28 days old plants were excised and cultured on MS medium supplemented with TDZ and NAA or in combination with Zeatin. In all of the media compositions tested, combination of TDZ 0.5 mg/L, Zeatin 0.5 mg/L, and NAA 0.1 mg/L was found to be the best medium for shoot bud initiation. Young petiole was the most appropriate explant type for the plant regeneration as well as genetic transformation in hot pepper. In this study, HpMADS1 gene isolated from hot pepper was introduced using Agrobacterium-mediated transformation system. Based on the analysis of Southern blot and RT-PCR, HpMADS1 gene was integrated in the hot pepper genome. It has been known that floral organ development is controlled by a group of regulatory factors containing the MADS domain. Morphological characteristics in these transgenic plants, especially flowering habit, however, were not significantly altered, indicating this MADS gene, HpMADS1 may be non-functional in this case.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.263-268
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• 2014

This research was performed to investigate the effect of light source and light quality in night break treatment on the growth and flowering of standard chrysanthemum. It was processed 4 hours (22:00-02:00) night break using LED 590, 610, 630, 660, 680nm and fluorescent lamp (mixed light of 480+540+610nm) in standard chrysanthemum 'Baekma' and 'Jinba' for 40 days from transplanting. The days to flower budding from short-day treatment of 'Baekma' were the longgest at fluorescent treatment (21.3 days) and were the shorttest at LED 590nm treatment (15.8 days) among all treatments. The days to flower budding from short-day treatment of 'Jinba' was longger with 18.0 days, 17.8 days, and 17.7 days at the fluorescent, LED 610nm, and 660nm treatments. And it was the shortest with 15.1 days in LED 590nm treatment. Similarly, the days to flowering from short-day treatment of 'Baekma' was the longgest with 56.9 days at fluorescent treatment, and was the shorttest in 51.6 days about LED 590 nm treatment. The days to flowering from short-day treatment of 'Jinba' was longer at fluorescent (56.0 days) and LED 660nm (56.7 days) treatments and was shortest at LED 590nm (52.9 days) among all treatments. Therefore, inhibition of flower bud initiation and flowering were the most effective under fluorescent treatment in case of 'Baekma', and fluorescent and LED 660nm treatments in case of 'Jinba'. The length and weight of cut flower of 'Baekma' and 'Jinba' were most excellent in fluorescent treatment in which the floral differentiation suppression effect was the best. Consequently, as to the growth and flowering of standard chrysanthemum, the treatment which was suitable as the light source and light quality for night break is regarded as the fluorescent lamp, and also under LED 660nm up to a certain level.

• Korean Journal of Plant Resources
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• v.21 no.5
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• pp.368-373
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• 2008

In order to investigate the effects of low temperature pretreatment of floral bud and plant growth regulators on anther-derived callus and shoot differentiation, anthers were cultured on 1/2 MS medium supplemented with 2,4-D, NAA, BA and TDZ. This plant depends on the plant growth regulators, for these anthers couldn't respond on 1/2 MS medium without plant growth regulators. 2,4-D was a prerequisite substance in this experiment, especially 52.6% of callus formation on MS medium with 2.0mg/L 2,4-D alone. However, the optimum medium was on 1/2 MS medium with 0.1 mg/L 2,4-D and 1.0mg/L BA for continuous growth and shoot differentiation from the anther. Calli derived from on MS medium with 2.0mg/L 2,4-D transferred to the 1/2MS medium with TDZ and BA. TDZ were less superior to BA, only one anther could produce shoot on MS media with 1.0mg/L TDZ. On the other hand, when the calli transferred to the medium with 3.0mg/L BA, adventitious shoots were proliferated, subsequently, regenerated shoots elongated from the embryogenic calli. After floral buds of one week before anthesis were incubated at $5^{\circ}C$ refrigerator for eight or fifteen days, anthers seperated from floral buds were cultured on 1/2MS medium supplemented with 0.1mg/L 2,4-D and 1.0mg/L BA. Callusing and shoot differentiation on anthers from treated at $5^{\circ}C$ for eight days were more effective than those of fifteen days or control.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.382-389
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• 2005

This study was conducted to establish the system of effective in vitro propagation by various explant sources culture of Bippeastrum hybridum Hort, 'Dazzler'. We tested the effects of optimal explant source, plant growth regulators on bulblet formation and plant regeneration. Callus was readily produced on the different tissues excised from floral buds whereas, bulbs and shoots were formed only on pedicel explants as compared with anthers, styles and ovaries. Pedicel is the best optimal explant for in vitro propagation. Two distinct pathways, organogenesis through callus and direct bulblet formation, could be recognized in pedicel culture. Up to the $80-100\%$ of bulblet formation and shoot organogenesis from the pedicel in fifteen days before anthesis were effectively induced by MS medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BA. Plantlet regeneration was successfully achieved from pedicel-derived callus, via shoot bud induction or direct bulblet formation. The bulblets with blooming flower were produced within 2 years.