• Korean Journal of Environmental Agriculture
• /
• v.5 no.2
• /
• pp.149-155
• /
• 1986

The fatty acid compositions of phospholipids extracted from leaves and leaf mitochondria, which were sampled from several horicultural plants grown under blue color-deficient sunlight (BCDS), were determined and compared with those from plants grown under natural white colored sunlight(WCS). It was found that the mitochondria isolated from plants grown under BCDS contained phospholipid whose degree of unsaturation in unit of number of double bonds per lipid molecule was remarkably higher than that from plants grown under WCS, the relative increment being $8{\sim}49%$. This was significantly larger than the relative increment, $4{\sim}8%$ for total phospholipid extracted from whole leaves grown under BCDS campared to WCS. This observation demonstrated that the blue light effect of sunlight on the chemical property of cellular membranes, as long as it was concerned with fatty acid composition, arose mainly at the mitochondrial membrane. Also observing that the degree of unsaturation of mitochondrial phospholipid was much lower than that of total phospholipid, it was interpreted that this was the consequence of rather active oxidative destruction of lipid-fatty acid components occuring in mitochondrial membrane by the reactive oxygen species, especially superoxide($O_2-$), which was known to be produced in mitochondrial inner membrane through the side reactions of the respiratory electron transport chain and also probably through the photosensitized reaction involving oxygen induced by blue colored light. Thus, it may be tentatively concluded that the extent of photosensitization in mitochondrial membrane could be considerably reduced under BCDS resulting in lowering of the $O_2-$ level in the respirating organelle The possible involvement of photodynamic action in membrane oxidation was also indicated by the fact that the typical fat-soluble antioxidant, ${\alpha}-tocopherol$, was found to be contained on a higher level in leaves under BCDS than those under WCS.

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

• Journal of Bio-Environment Control
• /
• v.19 no.4
• /
• pp.351-359
• /
• 2010

To establish the optimum artificial light illumination method for baby leaf lettuce in closed plant factory system, the effects of red/blue light quality and short-term light quality conversion on growth and anthocyanin content were investigated. The growth of 'Hongha' lettuce was most favorable under red single wavelength LED light after 23 days of treatment, sequentially followed by the growth under red/blue mixed light, blue light, and fluorescent light. Total anthocyanin content in the mixed red/blue light (R57-B43) was 4.1-fold and 6.9-fold increased compared to the red LED and fluorescent light, respectively. With increasing the blue light ratio to 43%, the growth of lettuce was significantly decreased, while the relative chlorophyll content and Hunter's $a^*$ value was increased, indicating that the red/blue light ratio inversely affects on growth and anthocyanin pigment development. By changing light quality from red to red/blue mixed light source (R57-B43) for 9 days before harvest, the growth rate decreased compared to the continuous red light illumination, while the anthocyanin content dramatically increased compared to either red LED or fluorescent light. Whereas, when the light source was changed to red light, the growth rate was increased but anthocyanin content was reversely decreased. The result demonstrated that both growth and anthocyanin expression could be effectively regulated by shifting of light quality between red and red/blue mixed light source at a specific growth stage of lettuce in a plant factory.

• Korean Journal of Plant Resources
• /
• v.12 no.2
• /
• pp.95-101
• /
• 1999

Higher and uniform germination should be necessary because many commercial pepper (Capsicum annum L.) seedlings were nowadays sold to farmer. The experiment was carried out to determine the effect of its cultivars (Daemyung; Wanggochu), GA$_3$ (concentration; period), light quality (red; far-red; blue; dark) during GA$_3$imbibition, and germination temperature (GT: 25 or 15$^{\circ}C$ constant; 25/15$^{\circ}C$ alternating) on the rate of germination done under incandescent lamps until 9 days after sowing. Final seed germination was not different between GA$_3$0 to 1.0 mM concentrations but the elapsed days to 50% germination $(T_{50})$ were more reduced by GA$_3$ treatment than water imbibition. Under $25^{\circ}C$ constant germination temperature, earlier germination was enhanced by GA$_3$treatment showing the lowest rate at darkness, although the final germination rates of water imbibition and GA$_3$ treatments were same. The final germination rates of alternating and 25 $^{\circ}C$ constant GT in cv. Daemyng was also equal, while the germination rates of $25^{\circ}C$ and 15$^{\circ}C$ constant GT were the highest and the lowest regardless of cultivars. There was no difference between light quality treatments impelled during GA$_3$ imbibition when light treated seeds were germinated at alternating and $25^{\circ}C$ constant GT. At 15$^{\circ}C$ constant GT, however, red light or dark treatment during GA$_3$imbibition increased the germination rate since 5 days after sowing.

• Journal of Bio-Environment Control
• /
• v.31 no.3
• /
• pp.180-187
• /
• 2022

In order to select suitable light in a plant factory, electric energy use efficiency and light use efficiency should be considered simultaneously to consider operating costs as well as quantitative and functional aspects. The growth characteristics, electric energy use efficiency, light use efficiency by light intensity, LED ratio, and photoperiod conditions were compared together. Light intensity is 60, 130, 230, and 320 µmol·m^-2·s^-1 treatments, and light quality is the mixing ratio of red light and blue light 8:2, 6:4, 4:6, and 2:8 treatments. Photoperiod is 9, 12, 15, and 18 hours treatments based on the daytime. In the light intensity experiment, the growth rate increased as the light intensity increased, but there was no significant difference in the light use efficiency. When comparing the leaf fresh weight per power consumption, only the 320 µmol·m^-2·s^-1 treatment group showed significantly low efficiency, and there was no significant difference in the other treatments, so 230 µmol·m^-2·s^-1, which produced the most, was the most efficient. In the light quality experiment, the ratio of red light and blue light was measured to be high at the same time as the growth rate and light use efficiency in RB 8:2, and there was no significant difference in color difference and flavonoids content, so a Red:Blue ratio of 8:2 was the most suitable condition. In the photoperiod experiment, the longer the photoperiod, the higher the growth rate. However, there was no significant difference in the growth rate over 12 hours of daytime, so 12 hours considering the light consumption efficiency was a suitable condition. Based on the above results, LED light environmental conditions for perilla growth in plant factories were light intensity, light quality, and day length of 230 µmol·m^-2·s^-1 or more, 8:2, and 12 hours or more, respectively.

• Journal of Ginseng Research
• /
• v.15 no.1
• /
• pp.21-30
• /
• 1991

This study was conducted to know the elects of light intensity of polyethylene net shading on the growth status, photosynthesis and root yield of ginseng plants. Polyethylene net shading of loft transmittance was the best one among light intensities of polyethylene net used in view of photosynthesis and decreasing of early leaf defoliation. According to increase of light intensity under the shading chlorophyll contents of ginseng leaves were decreased. As it was increased over 2 mg/g Photosynthesis and total saponin of leaves showed on the decrease remarkably. The rate of alternaria blight of ginseng plants showed the positive correlation between light intensity and leaking rate. The shading of 10% transmittance in root yield was increased by 40% in 6-year-old ginseng plant as compared with common straw shading, due to decreased missing plant and increased root weight.

• Journal of Biosystems Engineering
• /
• v.31 no.5 s.118
• /
• pp.449-453
• /
• 2006

Effect of light quality on plant temperatures at joining parts of grafted watermelon seedlings was investigated using a thermal imaging system in this study. Plant temperatures at joining parts lowered than those at stem region during graft-taking. However, difference in plant temperatures at joining parts and at stem region decreased by days after graft-taking. Plant temperatures of grafted seedlings graft-taken under white, blue, red, and blue + red fluorescent lamps repeatedly fluctuated high at photoperiod and low at dark period. Considering the variation of plant temperatures at joining pa퍼5, the illumination of blue and red light as well as white light will be effective for grafting of grafted watermelon seedlings. It is recommended that air temperature around grafted seedlings should be maintained at 27 to $29^{\circ}C$ for enhancing the physiological reaction of callus and for the smooth joining of scion and rootstock.

• Journal of Ginseng Research
• /
• v.12 no.1
• /
• pp.87-91
• /
• 1988

Photosynthesis rates of ginseng (Panax quinquefolium) leaves were measured in a controlled environment at $20^{\circ}C$ under the different monochromatic light such as white(W), red(R) and blue(B) to obtain basic information applicable to the colored shading material for the ginseng growth. Photosynthesis rate relative to white(W) light was generally higher in R and lower in B comparing to white(W) light. This difference was negligible at the close to the light-saturation point, whereas the difference among the monochromatic light was extended with decreasing the irradiant. It suggests that red is good in color of shading material for growth of American ginseng.

• Journal of Bio-Environment Control
• /
• v.22 no.4
• /
• pp.400-407
• /
• 2013

This study was performed to analyze the effect of light quality of discharge lamp on growth and phytochemicals contents of lettuce (Lactuca sativa L. cv. Jeokchima) grown under metal halide (MH) lamp, high-pressure sodium (HPS) lamp, and xenon (XE) lamp in a plant factory. Cool-white fluorescent (FL) lamp was used as the control. Photoperiod, air temperature, relative humidity, $CO_2$ concentration, and photosynthetic photon flux (PPF) in a plant factory were 16/8 h (day/night), $22/18^{\circ}C$, 70%, 400 ${\mu}mol{\cdot}mol^{-1}$, and 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. MH lamp had the greatest fraction of blue light (400-500 nm) of 23.0%. However, HPS lamp had the lowest fraction of 4.7% for blue light and the greatest fraction of 38.0% for red light (600-700 nm). At 11 and 21 days after transplanting, leaf length, leaf width, leaf area, shoot fresh weight, and shoot dry weight of lettuce as affected by the light quality of the discharge lamp were significantly different. The leaf area of lettuce grown under HPS, MH, and XE lamp increased by 45.7%, 16.3%, and 9.5%, respectively, as compared to the control. These results were similar for shoot fresh weight. Growth characteristics of lettuce grown under HPS lamp increased since HPS lamp had more fraction of red light. However, growth of lettuce grown under MH and XE lamp decreased since they had more fraction of blue light. As compared to the control, the ascorbic acid in lettuce leaves grown under discharge lamp decreased. The greatest anthocyanins accumulation of 0.70 mg/100 g was found at MH treatment. Anthocyanins content in lettuce leaves grown under XL and HPS lamp were 79.3% and 8.6%, respectively, compared with the control. Growth and phytochemicals contents of lettuce were highly affected by the different spectral distribution of the discharge lamp. These results indicate that the combination of discharge lamp or LED lamp for enhancing the light quality of discharge lamps is required to increase the growth and phytochemicals accumulation of lettuce in controlled environment such as plant factory.

• Korean Journal of Plant Resources
• /
• v.29 no.4
• /
• pp.363-375
• /
• 2016

Potentilla kleiniana is a perennial herb beloning to Rosaceae family. Herein we investigated the effect of light intensity, light quality and chemical elicitor on plant growth and the accumulation of bioactive compounds in P. kleiniana. After 60 days of cultivation under different shading level [0% (200 μmol·m⁻²·s⁻¹), 35% (95 μmol·m⁻²·s⁻¹), 55% (65 μmol·m⁻²·s⁻¹), 75% (40 μmol·m⁻²·s⁻¹)] in the greenhouse, chlorophyll and carotenoid content were the highest under 35% treatment, however, plant height, leaf number and biomass were the highest under non-shading. As a result of cultivation among strong light condition as a control, florescence and three mixture light sources [red:white:blue (RWB) = 8:1:1, red:blue (RB) = 8:2, red:green:blue (RGB) = 8:1:1] as treatments in plant growth chamber (25 ± 2℃, 185 ± 3 μmol·m⁻²·s⁻¹), growth, biomass, chlorophyll content low difference between total phenolic compouds and flavonoid content were higher under RWB treatment. DPPH radical elimination ability was the highest under all treatments especially florescence and RGB treatment except control. As a result of treating chemical elicitor [salicylic acid (SA), methyl jasmonate (MeJA)] concentration (0, 50, 100, 200 μM) respectively, plant height, petiole diameter and biomass were higher under non-treatment, MeJA 50 μM. It was investigated that fresh weight and dry weight under MeJA 50 μM treatment were especially a little high. Total phenolic compounds and flavonoid content of SA 50 μM treatment was the highest but DPPH radical elimination ability was significantly the highest under MeJA 200 μM (88.65%) and MeJA 50 μM (87.84%) treatment. Thus, this study suggested that we determined optimal shading and light quality in the greenhouse and plant growth chamber also confirmed bioactive compound content, antioxidant ratio increase according to different chemical elicitation concentration.