• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.175-182
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• 2012

Light characteristics of the monochromatic red(R), blue(B), green(G) and white(W) and the mixed LED (B-R LED) were investigated by light control a Spectrometer-MMS1 and an illuminometer. The power consumption of each LED was 1W and R LED has five wavelength bands(600nm, 640nm, 660nm, 680nm, 750nm). The light intensity of each LED was changed in a range 10~100%. As a results, the wavelength and the spectrum distribution of R LED increase with increasing light intensity but the wavelength of B, G, W LED decreases. It was found that illumination of each mononochromatic and B-R LED increases linearly with increasing light intensity. It was confirmed that the illumination intensity of R-B light has greater values than those obtained by monochromatic light at the same conditions.

• Journal of Bio-Environment Control
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• v.9 no.2
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• pp.94-100
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• 2000

This study was conducted to investigate the changes of electric potentials of leaf surface induced by environmental stimuli in plant. The values of electric potentials varied with different intervals of light on and off, and light qualities and moreover, their changes were also varied according to the time of a day. Additionally, stimuli such as candle light, wind, or 5$^{\circ}C$ cool water spray also evoked considerable changes in leaf surface electric potentials and their signal patterns varied with species of plants tested. In frequency analysis of electric potentials, the distribution values by FFT were highest in 1-10 Hz frequency zone by the majority of stimuli. These results suggested that changes in leaf surface electric potentials depended upon plant species even though stimulus was the same and vice versa.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.5-5
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• 2020

일반적으로 식물의 공급방법은 채집과 재배로 나눌 수 있으며, 자원식물은 상용화를 위해는 안정적 공급이 선행되어야 하므로 재배를 선호하고 있다. 재배방식은 다시 노지재배, 시설재배, Indoor Farm(식물공장)으로 나눌 수 있으며, 우리나라는 시설재배 중 비닐하우스 활용이 활발한 나라로 평가된다. 노지재배에 비해서는 시설재배가 온/습도 관리에 대해 장점을 가지고 있으며, Indoor Farm(식물공장)은 광량, 광질 및 일조시간까지 전체 생육조건의 조절이 가능하지만 초기투자비용 및 운영비용 등으로 인해 경제성이 낮아 아직까지는 상용되고 있지 않다. 자원식물의 경우 부가가치가 높아지는 후방사업으로 발달할 수 있으나, 화장품, 기능식품 또는 의약품으로 개발하기 위해서는 일정한 품질을 확보하여야 한다. 자원식물 재배 시 특정 성분의 함량을 일정하게 유지하기 위해서는 온/습도, 광량, 광질 등 생육환경을 관리할 수 있는 시설재배가 노지재배에 비해 적합하다. 하지만, 일부 자원식물의 경우에는 위도, 일조량 등으로 인해 국내에서는 시설재배로도 적절한 생육조건을 제공할 수 없어서 상업화하지 못한 경우가 많았다. 이에, (주)넥스트온은 Indoor Farm(식물공장) 전문기업으로서, 기존 자원식물 중 국내에서 시설재배로는 적절한 품질 확보가 불가했던 자원식물 및 특수 생육환경에서만 자생하는 희귀 자원식물의 양산화에 노력하고 있다.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.291-297
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• 2013

The objective of this study was to know the growth response and light use efficiency of leaf lettuce (Lactuca sativa L.) 'Yorum Cheongchukmyeon' (green leaf lettuce) and 'Hongyom Jeokchukmyeon' (red leaf lettuce) under different RGB (Red:Green:Blue) ratio in a closed-type plant factory system. The plants were hydroponically cultured with a 12-h photoperiod at $20{\sim}25^{\circ}C$, 60~70% RH and 600~900 ${\mu}mol{\cdot}mol^{-1}$ $CO_2$. The light treatments were combined in three colors LEDs (red, blue, and white) and RGB ratios (1 : 4 : 5, 5 : 0 : 5, 5 : 2 : 3, 7 : 0 : 3, 7 : 1 : 2, and 8 : 1 : 1), however, as the light intensities of treatments were different. Growth characteristic response in both lettuces were significantly as affected by interaction between cultivar and light quality, when they were grown under different light quality conditions. Plant heights of green and red leaf lettuce were the lowest in 1 : 4 : 5 and 8 : 1 : 1, respectively. The highest length and number of leaf were showed 8 : 1 : 1 and 7 : 0 : 3 for the green and 5 : 2 : 3 and 8 : 1 : 1 for the red, respectively. Shoot dry weights of green and red leaf lettuce were the heaviest in 7 : 0 : 3 and 8 : 1 : 1, respectively. Leaf width and leaf shape index were significant about cultivar and light quality. Leaf widths of green and red leaf lettuce were the largest in 8 : 1 : 1 and 5 : 2 : 3, respectively. Leaf shape index of green and red leaf lettuce were the largest in 1 : 4 : 5 and 1 : 4 : 5, respectively. Shoot fresh weight and light use efficiency were significant about cultivar and light quality. Shoot fresh weights of green and red leaf lettuce were the heaviest in 7 : 0 : 3 and 8 : 1 : 1, respectively. Light use efficiencies of green and red leaf lettuce were the highest in 7 : 0 : 3 and 5 : 0 : 5, respectively. These results suggested that the ratio of RGB was 5~7 : 0~2 : 1~3 to cultivate leaf lettuce in a plant factory system.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.193-200
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• 2017

BACKGROUND: Plant growth under smart greenhouse (that is plant factory system) conditions of an artificial light type is significantly depending on the artificial light sources such as a fluorescent lamps or Light-Emitting Diodes (LEDs) with specific spectral wavelengths regardless of the outside environmental changes. In this experiment, characteristics on the growth and compound synthesis of kale seedlings affected by light qualities and intensities provided by LEDs were mentioned. METHODS AND RESULTS: The kale seedlings which developed 3~4 true leaves were exposed by fluorescent lamps or LEDs lights of red (R), blue+white (BW), blue+red (BR) with 50 (L) or $100(H){\mu}mol/m^2/s^1$ photosynthetic photon flux (PPF) under hydroponic culture system of deep flow technique for 50 days. Shoot fresh weight increased under the RH, BWH, and BRH treatments with higher PPF. Shoot elongation of the seedlings decreased, and polyphenol synthesis promoted by the higher light intensity conditions. Sugar synthesis in the leaves was above 2 times greater under the RH treatment of monochromic red light quality with $100{\mu}mol/m^2/s^1\;PPF$ than $50{\mu}mol/m^2/s^1\;PPF$. CONCLUSION: The results show that the control of light quality and intensity in the smart greenhouse conditions with artificial lights significantly affects the growth and compound synthesis in the fresh kale leaves with higher culture efficiency compared to the conventional soil culture under greenhouse or field conditions. Researches on the optimum light intensities of the LEDs with special spectral wavelengths are necessary for maximum growth and metabolism in the seedlings.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.143-149
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• 2019

This study was conducted to investigate the graft-taking and growth of grafted cucumber seedlings as affected by light quality and blink cycle of LED modules. Four light quality treatments, namely blue, red, blue+red, white LED and four blink cycle levels of 5s/5s, 7s/3s, 9s/1s and control were provided to investigate the effect of lighting quality and blink cycle on the graft-taking and growth of grafted cucumber seedlings. Photoperiod for the control was 12/12 h. Photosynthetic photon flux, air temperature, and relative humidity for healing were maintained at $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $25^{\circ}C$, and 90%, respectively. There was no significant difference in graft-taking of grafted cucumber seedlings according to light quality except the blue LED with the blink cycle of 5s/5s. Regardless of the blink cycle, there was no significant difference in graft-taking of cucumber seedlings healed under red, blue+red, and white LED modules. These results implied that the effects of light quality and blink cycle on the graft-taking were not significant. Differences in the leaf length, leaf area, and fresh weight of cucumber seedlings healed blue or red LED with the blink cycle of 9s/1s were found to be significant. There was no significant effect of the blink cycle on the growth of cucumber seedlings healed under white LED modules. The prices of white LED are gradually falling due to increased demand. Considering the manufacturing unit price of white LED modules, the cost savings of 10-15% are expected as compared to the conventional blue/red LED modules. Therefore, it was concluded that the use of white LED modules will be economical as an artificial lighting sources for healing of grafted seedlings.

• Journal of Ginseng Research
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• v.23 no.1 s.53
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• pp.1-7
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• 1999

Photosynthetic rates and leaf bleaching were measured under light of far-red, red, orange, green, blue and white in order to clarify the effect of light qualities on photosynthesis in Panax species, P. ginseng and P. quinquefolium. Photosynthetic rate of P. ginseng and P. quinquifolium showed higher in the order under the light of red > orange > blue > white > green. Degree of leaf bleaching in P. quinquifolium showed severer in the order under the light of far-red > red > white > blue > orange > green. These suggest that shading material with blue or orange color is good for ginseng growth. As for the effect of temperature, the photosynthesis was increased with increasing temperature untill $25^{\circ}C$ and thereafter decreased. Therefore, it was clarified that the optimum temperature for photosynthesis of P. ginseng and P. quinquefolium was $25^{\circ}C$. And the dark respiration rate of ginseng leaf also increased with increasing air temperature. Especially, the dark respiration rate increased by $80\%$ for P. ginseng and by $73\%$ for P.quinquefolium at above $30^{\circ}C$ as compared with $25^{\circ}C$. In general, the photosynthesis rate was higher in P. quinquifolium than in P. ginseng and ranged from 3.54 to 4.04 mg $(CO_2{\cdot}dm^{-2}{\cdot}hr^{-1})$ for P. quinquefolium and from 2.08 to 2.59 mg$(CO_2{\cdot}dm^{-2}{\cdot}hr^{-1})$ for P. ginseng.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.475-483
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• 2015

We examined the effects of light colors (wavelength) and light quantities on the yield ratio and quality of cultivated cowpea sprouts. All light colors resulted in a lower cowpea sprout yield ratio compared to the untreated condition (darkness), but were similar in hard seed ratio. All light colors promoted the growth of the epicotyl and root when compared to the untreated condition, but limited the growth of the hypocotyl. White light (458 nm) significantly improved grade by increasing the lightness of the cotyledon and the hypocotyl and the yellowness of the hypocotyl. The Fe content of cowpea sprouts was higher in those grown under red light (632 nm), and the total amino acid content was higher for those grown under yellow light (560 nm), white light (458 nm), and blue light (460 nm) compared to plants grown in the untreated condition (darkness). The yield ratio of cowpea sprouts was lower in the yellow light condition (560 nm) at lower light quantity, but no differences were observed at other light colors and quantities. The lightness and yellowness of cowpea sprouts was higher in the yellow light (560 nm) and red light (632 nm) at lower light quantity, redness was lower. No significant differences were observed in the content of normal and inorganic components according to the light quantities of each light color, except that Fe content was higher in sprouts grown under red light (632 nm) as light quantity increased. Total amino acid content was slightly higher in sprouts grown under white light (458 nm) and blue light (460 nm) as light quantity increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.184-191
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• 1989

The effect of various supplementary light sources on the agronomic characteristics has been investigeted for generation acceleration of barley in green house with the condition of 15$^{\circ}C$ and 8 hrs. day light followed by each supplementary light sources including incandescent electric lamp (IN), Blue fluorescent lamp(BF). day-light fluorescent lamp(DF), Biolux lamp(BL), BL+BF, In+BF and IN+BL. Leaf number of main stem, leaf area, culm length, dry matter yield of shoot, number of grain per spike, grain yield per plant were most sharply decreased with the exposition of IN, while flag-leaf emergence on main stem and I, 000 grain weight were earlist and heavist respectively with the exposition of IN. In appeared to be best light source for shortening the days to heading, but IN + BF will be most desirable light source with considering both days to heading and adequate yield at the same time.

• Proceedings of the Korean Society of Crop Science Conference
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• 1995.10a
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• pp.52-53
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• 1995