• Korean Journal of Agricultural Science
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• v.40 no.4
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• pp.297-303
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• 2013

This study was carried out to examine the effect of Red LED (660 nm) and fluorescent lamp for night break (NB) treatments of each 3 hours (22:30-01:30), 4 hours (22:00-02:00) and 5 hours (21:30-:02:30) per day for 53 days on flower bud initiation and growth in Chrysanthemum cv. 'Baekma' and cv. 'Jinba'. The days to flower budding after short-day treatment in 'Baekma' was longer at fluorescent lamp 4 hr (21.0 days) and 5 hr (20.5 days) NB, and it was shorter at Red LED 3 hr (14.2 days). The days to flowering after short-day treatment in 'Baekma' was longer at fluorescent lamp 4 hr (54.0 days), 5 hr (53.5 days) NB, and Red LED 5 hr (53.3 days), and it was shortest at Red LED 3 hr (50.2 days) NB treatment among all treatments. The days to flower budding after short-day treatment of 'Jinba' was longer at fluorescent lamp 4 hr (20.6 days) and was shorter at Red LED 3 hr (14.1 days) among all treatments. Similarly, the days to flowering after short-day treatment of 'Jinba' was longer at fluorescent lamp 4 hr (55.3 days) and was shortest at Red LED 3 hr (50.2 days) among all treatments. Therefore, inhibition of flower bud initiation was the most effective under fluorescent lamp 4 hr treatment. The length of cut flower of 'Baekma' was increased by fluorescent lamp 4 hr, 5 hr, and Red LED 5 hr, but of 'Jinba' was longer at LED 4 hr and 5 hr treatment. The weight of cut flower of 'Baekma' was heaviest at fluorescent lamp 5 hr treatment and was at Red LED 5hr treatment for 'Jinba' even though there was not statistically significant difference between 'Baekma' and 'Jinba'. Consequently, under fluorescent lamp 4 hr for night break was the most effective on flower bud initiation, flowering inhibition and cut-flower characteristics in 'Baekma' and 'Jinba'.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.490-498
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• 2017

The in vitro growth of virus-free sweet potato [Ipomoea batatas (L.) Lam.] plantlets was investigated under different light sources: fluorescent lamp (control); red (660 nm), blue (460 nm), white light-emitting diodes (LED), and two mixtures of blue and red LED (R:B = 8:2, and 7:3). Single node explants (10 mm) of three cultivars ('Matnami', 'Shincheonmi', and 'Yeonhwangmi') were cultured on Murashige and Skoog medium supplemented with $0.2mg{\cdot}L^{-1}$ 6-benzyladenine for 4 weeks. Explants were exposed to $150{\pm}5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux at a distance of 20 cm, constant temperature of $25^{\circ}C$, and under 16/8-h (day/night) photoperiod. Using the same method, the in vitro growth of 10 cultivars under red LED was also compared. After 3 weeks, vine length was highest in plantlets cultured under red LED, and lowest in plantlets cultured under blue LED. Fresh and dry weights were also greatest in plantlets cultured under red LED. Compared to the control, vine thickness was significantly higher in plantlets grown under white LED and the 7:3 R:B LED mixture. Significant differences were observed among the 10 cultivars grown under red LED. 'Matnami', 'Shincheonmi', and 'Shinhwangmi' all had excellent vine lengths, and fresh and dry weights. Compared to the control, vine elongation of sweet potato plantlets was most effective under red LED, and culture duration was about 1 week shorter.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.253-257
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• 2011

This study was carried out to investigate the effect of different light emitting diode (LED) irradiation on the growth of paprika (Capsicum annuum 'Cupra'). The plants were irradiated by red (660 nm), blue (460 nm) and red + blue (4 : 1) light emitting diodes above 50 cm for 5 hours after sunset. Photosynthetic photon flux (PPF) irradiated by red, blue and red + blue LED were $79{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $75{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and $102{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ respectively. Leaf temperature of paprika grown under blue LED irradiation was the highest of $18.6^{\circ}C$. Fruit temperature was the highest under in the control (no irradiation) but it was lower than leaf temperature. There was influence of LED irradiation on the paprika plants height; under blue irradiation the plant height was the shortest, while under in the control plant height was the highest. The leaf size of under different LED irradiation was bigger than that of in the control. Mean fruit weight under different LED irradiation was significantly increased; however number of fruits and marketable yield per plant were significantly decreased as compared to the control.

• Mycobiology
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• v.41 no.1
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• pp.63-66
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• 2013

This study was conducted to identify a suitable color of light for development of the fruit body in Hypsizygus marmoreus. To accomplish this, samples were irradiated with blue (475 nm), green (525 nm), yellow (590 nm), or red (660 nm) light emitting diodes (LEDs) to induce the formation of fruiting bodies after mycelia growth. The diameter and thickness of the pileus and length of stipes in samples subjected to blue LED treatment were similar to those of subjected to fluorescent light (control), and the lengths of the stipes were highest in response to treatment with the red LED and darkness. The commercial yields of plants subjected to blue and green LED treatment were similar to those of the control. In conclusion, cultivation of H. marmoreus coupled with exposure to blue LED is useful for inducing high quality fruit bodies as well as higher levels of ergosterol, DPPH radical scavenging activity, total polyphenol content and reducing power.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.7-7
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• 2019

우리나라에서의 대마는 마약류로 분류되어 기호용과 의료용 모두 법적인 제재를 받아왔으나 최근에 의료용 대마가 법적으로 허용이 되어 환자들에게 처방 받을 수 있게 되었다. 하지만 우리나라 사람들에게 대마는 환각성분을 가진 마약류로 깊이 인식되어 왔으며 의료용 대마에 대한 연구는 거의 전무한 실정이다. 노지재배에서 발생할 수 있는 범죄의 위험성, 자연교배에 의한 품질저하를 피할 수 있으며 재배조건(양액, 광조건, 광주기, 대기환경조성) 등을 제어할 수 있는 밀폐형 LED 식물공장은 의료용 대마 생산에 제일 적합한 모델이 될 수 있다. 식물체의 광합성은 가시광선 중 특정 파장 450nm 청색광과 660nm 적생광을 주로 이용하며 'LED (Light Emitting Diode) 발광다이오드'는 식물체의 광합성에 적합한 파장으로 광원을 조사할 수 있는 장점이 있다. 이러한 LED를 이용한 광합성은 식물체의 2차 대사물질 Anthocyanins, phenolic compounds 등의 향상과 생육에도 긍정적인 영향을 미치며 식물 뿐만 아니라 광합성을 하는 미세조류(micro algae)에서도 이용이 가능하며 해마토 코쿠스(Hematococcus)의 세포증식과 항산화물질 아스타잔틴(astaxathin)생산에 유용하게 쓰이고 있다. 최근 미국과 다른 나라에서도 기호용, 의료용 대마사업에 대한 관심이 높아지고 있으며 캐나다와 미국에서는 밀폐형 유리온실과 식물공장을 이용한 의료용 대마를 생산, 추출, 가공까지 하여 산업적인 영역을 넓히고 있는 실정이다. 특히, 실내재배에서는 광원이 필수적인 요소이며 식물생육에 선택적인 파장을 조사할 수 있는 LED와 재배조건을 정밀하게 제어할 수 있는 밀폐형 식물공장을 이용한 의료용 대마 생산에 대한 연구가 절실히 필요한 시점이다.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.175-179
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• 2011

Light wavelength is the major factor of fruit body development associated with mushroom cultivation, but its wavelength range in Pleurotus eryngii is poorly understood. Using four kinds of light emitting diode (LED) including blue (475 nm), green (525 nm), yellowed (590 nm) and red (660 nm), we investigated to elucidate suitable light wavelength during primordium formation and fruit body development of P. eryngii on bottle cultivation. Primordia formation did not occur in blue light and red light. The morphological properties of fruit body in fluorescent lamp and blue light irradiation were showed thicker and larger pileus than those in other LEDs. However, length of stipe in fluorescent lamp and blue light was shorter than that of other LEDs. The DPPH radical was high in blue light, green light, and yellow light except for red light, and the polyphenol was high in four kinds of LED sources. And ergosterol was the highest in the green light. Thus, the high-quality mushroom production of P. eryngii is possible to green light condition considering productivity and functional materials.

• Journal of Ginseng Research
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• v.36 no.2
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• pp.198-204
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• 2012

An light-emitting diode (LED)-based light source was used as a monochromatic light source to determine the responses of raw ginseng roots (Panax ginseng Meyer) to specific emission spectra with respect to the production of ginsenosides. The ginsenoside content in the ginseng roots changed in response to the LED light treatments at $25^{\circ}C$ relative to the levels in the control roots that were treated in the dark or at $4^{\circ}C$ for 7 d. Ginseng roots were exposed to LEDs with four different peak emission wavelengths, 380, 450, 470, and 660 nm, in closed compartments. Compared with the control $4^{\circ}C$-treated roots, roots that were treated with 450 and 470 nm light showed a significantly increased production of ginsenosides (p<0.05), with increases of 64.9% and 74.1%, respectively. The contents of the ginsenosides $Rb_2$, Rc, and $Rg_1$ were significantly higher (p<0.05) in the 450 and 470 nm-treated root samples. The ratio of protopanaxadiol ginsenosides ($Rb_1$, $Rb_2$, Rc, and Rd) to protopanaxatriol ginsenosides ($Rb_1$, $Rb_2$, Re, and Rf) was significantly higher (p<0.05) in the 450 and 470 nm-treated root samples than in the control $4^{\circ}C$-treated roots. This is the first report that demonstrates the increase and conversion of ginsenosides in raw ginseng roots in response to exposure to LED light.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.171-180
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• 2020

The effect of three different light qualities on growth, photosynthesis, quality and safe parameters of hydroponic cultivated spinach (Spinacia oleracea L.) were investigated indoor. Three different light qualities were created of red (660 nm), blue (450 nm) and green (550 nm) LEDs corresponding at ratio R660/B450 = 4/1 (RBL); R660/B450/G550= 5/2/3 (WWL); R660/B450/G550 = 1/1/1 (WL), which were tested at the same intensity (PPFD =190 μmol m^-2 s^-1). The results showed that the plant height and leaf number were the lowest in WL treatment. The SPAD, Net photosynthesis rate Pn, Fv/Fm, Leaf area index LAI values and all parameters of root characteristics were the highest in RBL treatment and were significantly different from two others. Fresh weight of stem, leaf and root, dry weight of root in the three light qualities were significantly different. In contrast, the highest K⁺ content in WL was different from WWL and RBL treatments, while Ca²⁺ and Fe²⁺ content were the highest in the RBL treatment. Vitamin C content was significantly different between the three treatments. nitrate and oxalic acid contents were the highest in WL treatment, whereas soluble-solids contents and vitamin C contents were the highest in RBL treatment. Oxalic acid, nitrate contents were observed tending reduced under WWL although oxalic acid content in RBL treatment was not different from WL and WWL treatments. In all three different light treatments were not detected Salmonella, E.coli. Our results suggest that RBL may be appropriate light for growth of spinach, but supplementary green light to a combination of red and blue LEDs at the reasonable rate can change the quality of spinach in a positive direction. Hydroponic cultivated spinach was safe for users.

• Journal of Biomedical Engineering Research
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• v.40 no.4
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• pp.125-131
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• 2019

As a non-invasive method for alleviating allergic rhinitis, there has been a recent ongoing research in the treatment of light from light emitting diodes (LEDs) and lasers. A total of 15 subjects diagnosed with allergic rhinitis were selected for this study. Red and near infrared light emitted from LEDs with wavelengths of 660nm and 940nm were illuminated three times daily (three minutes per cycle) for a total of two weeks. The degree of nasal congestion, runny nose, sneezing and nasal itching was evaluated by questionnaires before and after the test. Also, the serum IgE (Immunoglobulin E) was measured and compared before and after the test. As a result, the total score of symptoms of allergic rhinitis was decreased by 67% after the test (P<0.01). The level of IgE was decreased by 17% after the test (P<0.05). In conclusion, the non-invasive LED phototherapy method using red and near-infrared LED light was effective in alleviating symptoms of allergic rhinitis. There were no adverse effects or complications reported during and after the test.

• Journal of the Semiconductor & Display Technology
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• v.17 no.2
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• pp.36-40
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• 2018

Point LED applied in Korea is applied to communication RCLED, but it is designed to be suitable for communication, so it does not meet requirements in fiber coupling rate and optical output. - Currently, domestic optical pipe manufacturers use general LEDs for light emitting devices, but Japanese products use high power point LEDs to develop superior point LED (RED 620 ~ 660nm).