• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.228-233
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• 2013

This study was conducted to examine the effect of light intensity and photoperiod of white LEDs as the artificial light source on the growth of leaf lettuce (Lactuca sativa L.) 'Seonhong Jeokchukmyeon' in a closed-type plant production system. Seedlings, transplanted at a density of $20cm{\times}20cm$ in a completely randomized design, were grown under white LEDs (FC Poibe Co. Ltd., Korea), at one of the 3 light intensities (100, 200, or $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$), and each with one of 3 photoperiods [12/12, 18/6, or 24/0 (Light/Dark)]. Plants were cultured for 22 days under the condition of $21{\pm}2^{\circ}C$, $60{\pm}10%$ RH, and $400{\pm}50{\mu}mol{\cdot}mol^{-1}\;CO_2$. The greatest leaf length and width, fresh and dry weights, and total anthocyanin content were obtained in the 24/0 photoperiod, regardless of the light intensity. Length of the longest root, fresh and dry weights, and number of leaves were greater in light intensity of $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ than 100 or $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Chlorophyll value was the greatest in the photoperiod 12/12 than 18/6 or 24/0. The results obtained suggest that plant grew the best kept by light intensity at 200 or $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and photoperiod of 12/12 or 18/6.

• Korean Journal of Plant Resources
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• v.24 no.5
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• pp.613-621
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• 2011

Plastic house and laboratory experiments were conducted to determine the effects of substrate components and shade degrees on plant growth and physiologically-active substance content and antioxidant activity of Panax ginseng. No significant difference in growth characteristics among substrates was observed. However, shade treatment also significantly reduced leaf area, chlorophyll content, root length, and shoot and root fresh weight (P<0.05) with increasing of the degree. Total phenolics level [mg ferulic acid equivalents (FAE) $kg^{-1}$ DW] was higher in root parts (25.8 to 28.4 mg $kg^{-1}$) than shoot parts (20.7 to 23.8 mg $kg^{-1}$) of Panax ginseng, and with shade (23.7 to 28.4 mg $kg^{-1}$) than without shade (20.7 to 25.8 mg $kg^{-1}$). However, total flavonoids [mg naringin equivalents $kg^{-1}$ DW] was more detected in the shoot part (17.4 to 26.8 mg $kg^{-1}$) than in the root part (6.7 to 7.0 mg $kg^{-1}$) of Panax ginseng. Methanol extracts from the Panax ginseng plants dose-dependently increased DPPH free radical scavenging activity as a antioxidant potential, and the activity was higher in shoot parts (31.1 to 36.5%) than in root parts (24.9 to 28.7%), and without shade than with shade. In conclusion, shade affects plant growth as well as physiological activity of Panax ginseng under plastic house condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.2
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• pp.171-181
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• 2021

The purposes of this study were to determine how changes in temperature affect germination rates and growth of hulled and dehulled barley, malting barley, and naked oat plants, and to measure chlorophyll content, photosynthetic efficiency, and secondary compounds (total phenol, total flavonoid, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) in plants grown at 13℃ or 25℃). Various types of barley seeds were collected from areas with ideal conditions for barley cultivation, hereinafter referred to as IA, and also from areas where barley cultivation is more difficult due to lower temperatures, hereinafter referred to as LTA. Seeds were tested for seed vigor. While there were significant differences in the electrical conductivity values between seeds collected from certain specific areas, no significant differences were evident between IA and LTA seeds, regardless of the type of barley seed. When plants were grown at 25℃, there were no significant differences in germination rates, plant height, root length and shoot fresh weight between plants originating from IA and LTA. However, there were differences in the measured parameters of some specific seeds. Similarly, under the low temperature condition of 13℃, no differences in the emergence rate, plant height, and shoot fresh weight were evident between plants originating from IA or LTA, regardless of the type of barley. However, there were differences between some specific seeds. One parameter that did vary significantly was the emergence date. Hulled barley and malting barley emerged 5 days after sowing, whereas naked oats emerged 7 days after sowing. There were no differences in the chlorophyll content and photosynthetic efficacy, regardless of the type of barley. There were no significant differences in total phenol, total flavonoid content, and DPPH radical scavenging activity between plants originating from IA and LTA, regardless of the type of barley. However, there were differences between some specific seeds. In particular, for malting barley the total flavonoid content differed in the order of Gangjin > Changwon > Haenam = Jeonju > Naju. The results indicate that crop growth, yield and content of secondary compounds in various types of barley may be affected by climate change.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.19-25
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• 2014

In this study, we analyzed the growth characteristics of red lettuce under Light-emitting diode (LED) light environment as well as the change of vitamin C and anthocyanins of lettuce. We made five monochromatic light treatments (red 647 nm, 622 nm, blue 463 nm, 450 nm, White), six mixed red (R) and blue (B) light treatments (R : B = 9 : 1, 8 : 2, 7 : 3, 6 : 4, 5 : 5) and red + white, and three light treatments made according to photoperiod of LED with lighting sources ratio of red : blue (R : B = 8 : 2(18/06 h, 15/09 h, 12/12 h)). It was composed of totally 14 control beds. As a result, the red lettuce the most developed leaf height, leaf numbers and fresh weight under red single light, root length and leaf developed when grown under blue single light. Therefore, red light were related to above part of the lettuce, blue light were related to the growth of the underground part of lettuce. Case of the mixed light, leaf height, leaf numbers, fresh/dry weight of above and underground part were highest red + white light and root length and chlorophyll content were highest under red 7 : 3 blue light. Result of growing investigation by photoperiod, the red lettuce were considered to be most effective in 15/09 h (on/off). The content of anthocyanins; the single light source, mixed light and light irradiation period were highest under blue light (463 nm), red 7 : 3 blue and 18/06 h (on/off) light irradiation, respectively. The vitamin C showed the lowest content of $1.26mg{\cdot}L^{-1}$ under the white light, but showed the greatest content of $3.02mg{\cdot}L^{-1}$ for the control group.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.441-446
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• 2004

To reduce water input by water-saving irrigation techniques a field study was carried out with three water managements, very shallow intermittent irrigation (VSII, 2cm), shallow intermittent irrigation (SII, 4cm) and traditional deep water irrigation (DWI, 10cm) for two years. Rice growth and grain yields of three water managements were not significantly different. However, when the water irrigation depth was decreased, the breaking and lodging resistance were increased and the roots were widely distributed into deeper paddy soil. More numbers of both annual and perennial weeds were occurred in VSII than in DWI at maximum heading stage and only the number of perennial weeds was three times in VSII than in DWI at heading stage. The total water inputs were 777, 654 and 527 mm in DWI, SII and VSII, therefore the water-saving rates of VSII and SII were $32.2\%\;and\;15.9\%$ compared to typical deep water irrigation. The water-productivity (Rice yield to water input) was highest in VSII as 0.94 and followed by SII as 0.76 and DWI as 0.63. In the face of water scarcity, it is very important to find or develope water saving irrigation system and find ways to increase the productivity of water used for rice cultivation.

• Korean Journal of Medicinal Crop Science
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• v.6 no.2
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• pp.121-125
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• 1998

This experiment was carried out to investigate the effects of direct seeding and planting of seedlings in different ages on yield and yield characteristics of Cynanchum wilfordii $H_{EMSLY}$. Emergence date was three days earlier in direct seeding compared to May 14 in plots planted with one - or three - year - old seedlings. Petiole length was 16cm and 26cm longer in direct seeding and 1 - year - old seedlings, respectively, compared to 279cm in plot of 3 - year - old seedling. Root diameter was 0.4cm thicker in direct seeding and 0.5cm thicker in 1 - year - old seedlings compared to 1.0cm in seedlings of three years old. Root length was 7.2cm shorter in direct seeding, but was 0.6cm longer in 1 - year - old seedlings than 32.2cm in seedlings of three years old. Yield increased by 29 % in direct seeding and 55% in seedlings of one year old compared to 1,403kg/l0a in 3 - year - old seedlings. In cultivation of Cynanchum wilfordii $H_{EMSLY}$, the suitable planting methods were direct seeding or the use of 1 - year - old seedlings which were profitable at higher density as $50{\times}10cm$.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.108-114
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• 2002

Cellular glass foam (CGE), the reprocessed glass, has a possibility as a component of vegetative propagation media of floricultural crops due to the its excellent air and water permeability, similar to that of perlite. An experiment was conducted to evaluate the rooting and growth thereafter of Kalanchoe blossfeldiana ‘Gold Strike’in media containing various volume ratios of granular rockwool, peat-moss, CGF and perlite. The particle size of CGF and perlite was 2.0~4.0mm and 1.2~4.0mm, respectively. Cuttings were rooted in a fog tunnel with a mean temperature of 18.2$^{\circ}C$ and RH of 66.7％ under a long day regime (14 h per day light period). Height, length of the longest root, stem diameter, no. of leaves, leaf area, percentage of rooted cuttings, shoot and root fresh weights, shoot and root dry weights, total chlorophyll concentration and physicochemical properties were measured. Cuttings rooted 100% in all treatments. Physicochemical properties in CGF and perlite-containing media showed little differences. The growth of rooted plants in the CGF-containing media was similar or rather superior to that in perlite-containing media. Consequently, CGF has a possibility as a vegetative propagation medium of Kalanchoe. To make wider commercial use of CGF, more demonstrative experiments and analyses are necessary.

• Journal of Bio-Environment Control
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• v.23 no.3
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• pp.199-204
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• 2014

This study evaluated the effect of water content in the substrate during pre- and post-grafting period on the survival rate and quality of tomato plug seedlings. Nine combinations of three water levels (high, medium, and low) were set up in the substrate of both scion and rootstock. The water content in the substrate of the scion did not affect the survival rate of grafted tomato seedlings, while the survival rate was statically different among the various water contents in the substrate of the rootstock. The maximum survival rates (100%) were observed in seedlings treated with high water levels in the substrate of the rootstock, and the survival rates declined with decreasing water content in the rootstock substrate. The growth characteristics were not significantly affected by different water content in the scion substrate, while they were statically different among the seedlings treated with various water contents in the rootstock substrate. The growth characteristics decreased with decreasing water content in the rootstock substrate. The highest value of compactness was observed in grafted seedlings, which combined medium water level in the scion and high water level in the rootstock substrate treatment. The root morphology of tomato seedlings was also affected by water content in the rootstock substrate. The total root surface area, total root length, and number of root tips decreased with deceasing water content in the rootstock substrate.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.673-679
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• 2012

This study was conducted to examine the effect of artificial light source and photoperiod on the growth of leaf lettuce (Lactuca sativa L.) 'Seonhong Jeokchukmyeon' in a closed-type plant production system. Seedlings were grown under 3 light sources, fluorescent lamp (FL, Philips Co. Ltd., the Netherlands), WL #1 (Hepas Co. Ltd., Korea), and WL #2 (FC Poibe Co., Ltd., Korea), each with 3 photoperiods, 12/12, 18/6, and 24/0 (Light/Dark). An irradiance spectrum analysis showed that FL has various peaks in the 400-700 nm range, while WL #1 and WL #2 have only one monochromatic peak at 450 and 550 nm, respectively. The greatest plant height, fresh and dry weights were obtained in the 24/0 (Light/Dark) photoperiod. The 24/0 (Light/Dark) photoperiod treatment promoted vegetative growth of the leaf area. Length of the longest root, number of leaves, fresh weight, and total anthocyanin contents were greater in FL than in either WL #1 or #2. The greatest chlorophyll fluorescence (Fv/Fm) was found in the 12/12 (Light/Dark) photoperiod with FL treatment. The energy use efficiency of the LED increased by about 35-46% as compared to FL. Results suggest a possibility of LED being used as a substitute light source for fluorescent lamp for lettuce cultivation in a plant factory system.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.284-291
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• 1997

This study was conducted to evaluate the optimum hydroponic system and nutrient solution for shortening the early growth period and quality improvement of dendrobium ( Dendrobium Phalaenopsis) seedlings. Dendrobium seedlings with 3 to 4 leaves were transplanted in the deep flow technique(DFT) system, aeroponic system, and ebb and flow system with different concentration of balanced nutrient solutions recommended by the Japanese Horticultural Experiment Station. Growth characteristics of shoot and root were recorded and evaulated among treatments. For autumn cultivation, plant height was the longest at the DFT system with quarter concentration of nutrient solution, where aeroponic system with half concentration of nutrient solution. Aeroponic system stimulated the root growth but fresh weight was observed in the plots of DFT system. For spring cultivation, pH values increased up 7.5 at the DFT and aeroponic system, where EC values did not fluctuate regardless of cultural system. Ebb and flow system showed the best result in the growth of plant followed by BFT system and aeroponic system. Higher concentration of nutrient solution within this range of treatment was recommended for the growth promotion of leaf length and width in DFT system. In conclusion, growth responses differed depending on the cultural system, concentrations of nutrient solutions and duration of cltivation.