• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.54-63
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• 2018

Red and blue lights are effective wavelengths for photosynthesis in plants. In this study, we determined the effects of various combined ratios of red to blue LEDs on the quality of cherry tomato seedlings prior to transplantation, and their subsequent effects on the yield and quality of tomato fruits after transplanting. Two-week-old cherry tomato seedlings (Solanum lycopersicum cv. 'Cuty') were cultivated under various combined ratios of red (R; peak wavelength 655 nm) to blue (B; 456 nm) LEDs [red:blue = 41:59 (59B), 53:47 (47B), 65:35 (35B), 74:26 (26B), 87:13 (13B), or 100:0 (0B)] and fluorescent lamps and raised for 27 days. The cherry tomato seedlings were subsequently transplanted into a venlo-type greenhouse and cultivated for 75 days. At the seedling stage, the shoot fresh weight of seedlings in all RB combined treatments, except 0B and 59B, was higher than that of the control after 27 days of LED treatment. Shoot dry weight and leaf area also showed trends similar to that of shoot fresh weight. The stem length was significantly higher in 13B, 26B, and 35B treatments compared with the control and other treatments. In particular, the stem length of 26B plants was approximately 3.2 times longer than that of 59B plants. At 37 days after transplanting, the number of nodes was significantly higher in 26B and 47B plants, and the plant height of 26B plants was significantly higher than that of control and 59B plants. Total fruit yield in 26B plants, which was the highest, was approximately 1.6 and 1.8 times higher than that in control and 59B plants, respectively. Thus, the results of this study indicate that various combined ratios of red to blue LEDs directly affected to the growth of cherry tomato seedlings and may also affect parameters of reproductive growth such as fruit yield after transplantation.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.42-48
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• 2017

This study was conducted to establish the optimal condition for in vitro propagation of Disporum sessile. In the experiments with different kinds of media (MS, B5 and WPM) and explant types for shoot induction and elongation, the highest number of shoot inductions (2.5/explant) was shown when the axillary bud explants were cultured on MS medium without plant growth regulators (PGRs). The best shoot elongation (7.2 cm) was also obtained when the apical buds were cultured on MS medium. The effect of BA pulse treatments with in vitro shoots was also examined. The highest in shoot induction (2.29/explant) and elongation (7.28 cm) was observed when the shoots from axillary buds were cultured on the media without PGRs. However, it decreased with increasing duration of BA pulse-treatment. The highest rooting rate (100%) and number of root inductions (21.3/explant) were achieved with 1.0 mg/L indole-3-butyric acid (IBA) treatment, whereas no differences were observed by different shoot types. The regenerated in vitro plantlets were hardened and successfully established in soil.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.197-203
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• 2011

This experiment was carried out to investigate the growth characteristics of virus-free sweetpotato in hydroponic bag culture. The rooted one-node and upper-shoot cuttings of 'Yeonhwangmi' and 'Mannamiwere' transplanted into the plastic bag (0.5 mm of thickness, $W300{\times}L1,200{\times}H120mm$) culture system filled with commercial horticultural media (TKS-2, Flora Gard Co.) and cocopeat + perlite (3 : 7, 5 : 5, 7 : 3, (v/v). Nutrient solution of National Horticultural Research Station in Japan was separately irrigated $3times{\times}30minutes$ per day (10:00, 14:00 and 20:00 with timer control) by the drip irrigation. The growth of two varieties was not significantly different among four substrates in 15 days, but it was excellent in commercial horticultural media (TKS-2) and cocopeat 3 : perlite 7 (v/v) in 20 days. The growth in 'Yeonhwangmiwas' promoted than that in 'Mannami', and the upper-shoot cuttings of 'Yeonhwangmi' and 'Mannami' showed a significant vine elongation (over 10 and 2 cm, respectively) compared to the one-node cuttings. Fresh weight and dry weight in cocopeat 3 : perlite 7 (v/v) were significant increased than that in cocopeat 7 : perlite 3 (v/v). Therefore, the bag culture system filed with cocopeat 3 : perlite 7 (v/v) was successfully applied on propagation of virus-free sweetpotato seedling, and the result expected that the bag culture system could be commercialized without high financial costs for farmers.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.317-323
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• 2010

This study aimed to examine a suppression effect of salinity on extension rate of stem elongation of cucumber seedlings (Cucumis sativus L.) grafted with roots of figleaf gourd plant. The effects of application methods, timings, and concentrations of two salt types, sodium chloride (NaCl) and calcium chloride ($CaCl_2$), were compared to untreated control plants. In result, an obvious suppression effect on the excessive elongation of stem was obtained by both sub-irrigated and medium-mixed NaCl salt. An improvement in quality of transplants was also obtained by the sub-irrigated NaCl salt. Foliar-applied NaCl caused visible leaf injury when the concentration was higher than 40 mM; but, with no effect on suppressing the stem elongation. When the NaCl was applied at 7 days after grafting, a higher concentration of NaCl was demanded for suppressing the stem elongation compared to an application at the day of grafting. No effect of the NaCl salt on the fresh weights of 36-day grown plants was observed; but, there was a negative effect on the number of female flowers at a high temperature season. Overall, the NaCl salt was more effective on slowing down the stem elongation and had the lower incidence of leaf injury than the $CaCl_2$ salt.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.235-238
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• 2015

Adventitious buds were obtained from isolated cotyledons cultured on MS medium with various concentrations of 6-benzylamino purine (BA) and thidiazuron (TDZ). The highest numbers of adventitious buds were obtained on MS medium supplemented with 0.2 mg/L BA. Experimental culturing with half the petiole portion and half with the terminal segments were grown on MS medium contained with 0.2 mg/L BA. Frequency of the adventitious bud induction was variable accordingly to the type of cultured explants. Explants with the half petiole showed the highest adventitious bud induction rate (80%) compared to explants of half with terminal segment (20%). An elongated shoot from the buds and growth of advent roots were both possible on the 1/2 MS medium without a plant growth regulator. These results offer an effective way in which clonal propagation can be accomplished.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.85-91
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• 1999

In sweet potato cultivars 'Mokpo #29' and 'Sanchunza', shoots from extplants were formed 100% on the MS medium with 0.1 ㎎/L NAA and 2.0 ㎎/L BA after 30 days of culture and roots produced from the base of stem at frequencies of 66.7% ('Mokpo #29') and 69.2% ('Sanchunza'), respectively, The media with 0.5∼4.0 ㎎/L BA were produced the greatest frequency of multiple shoot and the most of shoots developed rapidly into normal plantlets with rooting within 60 days of culture. Whereas the cultivar 'Keumsi' failed to produce normal shoot multiplication on the medium with cytokinins alone because of callusing of adventitious shoots. When single shoots with 1 to 2 nodes were excised from the multiple shoot or shoots covered with callus devoid of root and transferred to MS medium with 4.0 ㎎/L BA or kinetin. Host divided shoots showed the callus induction at the stem base and it was enable to obtain regenerated plantlets with shoot and root normally.

• Journal of Plant Biotechnology
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• v.29 no.1
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• pp.25-29
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• 2002

The study was carried out to establish an efficient protocol for shoot organogenesis and plant regeneration from stem explant cultures of Lycopersicon esculentum cv. Micro-Tom. The regenerated shoots obtained from stem explant cultures on solid MS medium containing the different concentrations of BAP. The highest number of shoots (5.3) per explant and shoot growth (0.7 cm) was obtained on MS medium containing 4.0 mg/L BA. The additions of AgNO$_3$ and putrescine substantially improved the shoot regeneration frequency, at the optimal concentration of 7 mg/L and 50 mg/L respectively. The regenerated shoots (about 1 cm) were normal and could be easily rooted with 0.1 mg/L IBA treatment. The rooted plants were hardened and transferred to vermiculite with a 92% survival rate where they grew normally.

• 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'.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.376-382
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• 2014

This work was conducted to investigate the variation of growth and yield among three generations ($TC_0$, $TC_1$, and $TC_2$) in the field cultivation of virus-free sweetpotato (Ipomoea batatas) plants. Virus-free generations of three cultivars ('Matnami', 'Shinhwangmi', and 'Yeonhwangmi') were cultivated with $75{\times}25cm$ planting density on May 20th, covered with black vinyl film. At 30 days after planting, vine growth in $TC_0$, $TC_1$, and $TC_2$ was significantly increased as compared to the farmer's plant, and vine length in $TC_0$ showed the highest growth among treatments. At harvesting time after 120 days, vine diameter, number of node, and number of branch in $TC_0$, $TC_1$, and $TC_2$ were more increased than farmer's plant, but were not statistically significant. Fresh weight of shoot in $TC_0$, $TC_1$, and $TC_2$ was significantly increased as compared to the farmer's plant, but was not statistically significant among generations or cultivars. Number of tuber per plant and mean weight of tuber in $TC_0$ and $TC_1$ showed significant increasement, but that in $TC_2$ did not show significant difference as compared to the farmer's plant. Weight of tuber per plant in $TC_0$, $TC_1$, and $TC_2$ was significantly increased as compared to the farmer's plant. Marketable yield, percentage of marketable tuber, and percentage of small tuber (40 to 200g) in $TC_0$, $TC_1$, and $TC_2$ was significantly increased as compared to the farmer's plant. The large tuber over 300g showed the lowest percentage in $TC_0$. Marketable yield in $TC_2$ was significantly decreased as compared to $TC_0$, and was not significantly different as compared to the farmer's plant. Marketable yield in 'Matnami' was highest among cultivars. From this results, Farmers are required to renew every three years to maintain the yield and quality of virus-free plants. However, the exchange period of virus-free plants is desirable to renew every 2 or 3 years according to the degree of virus reinfection.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.309-314
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• 1990

A pot experiment was carried out to find the effects of chemicals and its application time on the sterility and other agronomic characters of rice. Two rice cultivars, Samgangbyeo, a Tongil type, and Chuchungbyeo, a japonica type rice were treated with maleic hydrazide (6000ppm), ethephon (6000ppm) and GA3 (10ppm) at five different growth stages. The application times of chemicals were comprised of two different stages of stem elongation and booting and panicle emerging stage. Grain sterility and panicle length were measured for panicles per pot. Culm length was measured for pot basis. MH induced complete grain sterility in rice, but caused severe plant damage (phytotoxicity) ; restricted spike emergence and drying out of plant leaves, sheath and panicles. Ethephon induced 50-60% grain sterility in rice with the least in plant damage. GA3 was not effective in inducing grain sterility in rice, but it increased culm length. The earlier application of chemicals, the higher sterility was induced. Both MH and ethephon reduced culm length and grain yield. Also observed was the varietal response in the occurrence of to chemicals Samgangbyeo showed the higher response to chemicals than Chuchungbyeo.