• 한국해양학회지
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• v.21 no.2
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• pp.101-109
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• 1986

To clarify the light condition which influence phytoplankton ecology in Kyeonggi Bay, light intensity, compensation depth, extinction coefficient, transparency and suspended substances are studied from May 1981 to September 1982.Light intensities lie within adequate values for the phytoplankton growth from spring to autumn. However, in the winter season the light intensities show less than 4.8mw/$\textrm{cm}^2$ on the surface resulting lower than optimum irradiance. Light intensity could be a limiting factor for phytoplankton growth in winter. Compensation depths seasonally varied over an annual period in this study. Especially, in winter, compensation depths are confined to only 1-2m below the surface. Extinction coefficient(K) values are relatively high over an year cycle. K values is highest in winter and lowest in summer. Transparency shows seasonal variation. Tansparency is high in summer and low in winter. Thus low light intensity, low compensation depth, low transparency and high extinction coefficient in winter are due to the high turbidity and high concentrations of suspended substances. High concentrations of S.S. in winter result from the sediments and detritus resuspended by the winter turbulence induced by the strong winter winds and the convectional mixing. In summer, good light condition and low turbidity may result from the thermal stability of water mass preventing the resuspension of sediment particles.

• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.493-500
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• 1998

To investigate the effects of light intensity on the growth, and the critical minimum light intensity for growing of Cornus controversa seedlings at the stage of cotyledon, hypocotyl elongation, cotyledon expansion, the times of leaves appearance, dry weights of each organ, and specific leaf area(SLA) were measured on a growth chamber with several light intensity gradients(385, 32, 17, 8, and $5{\mu}mol\;m^{-2}s^{-1}$). There was a positive correlationship between the size of cotyledon and the biomass of cotyledon and total seedling. Hypocotyl was more elongated under relatively low light intensities, such as 32, 17, 8, and $5{\mu}mol\;m^{-2}s^{-1}$ than under $385{\mu}mol\;m^{-2}s^{-1}$ light intensity, however, dry weight of the hypocotyl was adverse. As the light intensities decreased, the leaf appearance was delayed and the number of leaves decresed. In addition, leaves did not appear under $8{\mu}mol\;m^{-2}s^{-1}$ and $5{\mu}mol\;m^{-2}s^{-1}$ light intensity. Although cotyledons were more fully expanded under 32 and $17{\mu}mol\;m^{-2}s^{-1}$ light intensities than $385{\mu}mol\;m^{-2}s^{-1}$ light intensity, the dry weights of cotyledons were greater under the high light intensity. The dry weight of cotyledon, hypocotyl, root and leaves showed a decreased pattern with decreasing light intensities, but root to shoot(hypocotyl+leaves) ratio rapidly increased. Roots did not develop below $8{\mu}mol\;m^{-2}s^{-1}$ light intensity. In conclusion, the results showed that the critical minimum light intensity for growing of Cornus controversa seedlings was above $17{\mu}mol\;m^{-2}s^{-1}$ light intensity.

• Proceedings of the KACD Conference
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• 2002.11a
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• pp.703-703
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• 2002

No Abstract, See Full Text

• Journal of Korea Foresty Energy
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• v.21 no.3
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• pp.46-53
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• 2002

The study was carried out to determine the growth and biomass production of deciduous trees including Betula pendula, Fraxinus rhynchophylla, Cornus controversa subjected to artificial shade treatment of three levels in nursery field. The results were as follows; The height growth of seedlings was no difference subjected to artificial shade treatment. The root collar diameters of the relative growth rates of seedlings grown in full sun showed 29-32% as compared with those subjected to the shade treatment of 7-10% light intensities of full sun. Corrus controversa of the root collar diameters of the relative growth rates were better in the seedlings grown in 26-34% light intensities of full sun. Total dry mass including the dry mass of leaves, shoot and root were as a whole decreased with shade treatment. The ratio of the dry mass of leaves and stem increased the dry mass of root. T/R ratio of the seedlings increased by decreasing the relative light intensity. And the T/R ratio of 7-10% light intensities of full sun was ranged from 1.00~2.27 were greater in the full sun light was ranged from 0.51~l.13. Light intensity by artificial shade treatment decreased in deciduous trees when compared on the whole, it showed tendency that SLA increases, increased that seeing resemblant tendency in LAR and LWR and changed of light intensity is strong, it increased that showed difference as statistical.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.169-174
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• 1982

Light intensities under and above shading material were measured at different layers (upper, middle and lower layers) and lines (lst, 3rd and 5th lines) on clear and cloudy days in S-year-old ginseng plant populations. Rates of photosynthesis and respiration were also measured in field. Light intensities of the 1st lines at upper and lower layers were relatively high as compared with the 3rd and the 5th lines, and there were no remarkable difference between the 3rd and the 5th line. But in middle layer, the light intensity of each line differed considerably. As compared with fair and clear day, the day of clear but much diffuse light showed high light intensity under shading. Relative light intensity was higher on cloudy day than on clear day. There were notable differences of photosynthetic rates among the lines and the rearest lines exhibited the lowest rates. But it was not considered that even the front plants demonstrated the maximum photosynthetic capacity.

• Animal cells and systems
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• v.14 no.2
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• pp.125-128
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• 2010

This study investigated the effect of different light intensities on first feeding of chub mackerel Scomber japonicus larvae. Fertilized eggs, obtained from LHRHa-induced spawning of captive broodstock, were stocked (60 larvae/l) into twelve 30-1 aquaria under light intensities of 0, 100, 200, 500 and 1000 lx, with three replicate aquaria per treatment. Temperature was maintained at $20^{\circ}C$ and salinity was 35 psu. Larvae were fed the rotifer Brachionus rotundiformis at a density of five rotifers/ml. Feeding incidence was measured as the percentage of larvae with prey in the digestive tract. Feeding intensity was evaluated as the number of prey in the digestive tract of the larvae. Larvae fed in darkness (0 lx) had significantly lower (P < 0.05) feeding incidence ($13{\pm}0.05%$ larvae with prey) and feeding intensity ($1.00{\pm}0.05$ rotifers per larva) than those larvae fed at 100 ($30{\pm}0.07%$, $1.17{\pm}0.09$ rotifers per larva), 200 ($43{\pm}0.08%$, $1.24{\pm}0.11$ rotifers larvae$^{-1}$), 500 ($53{\pm}0.08%$, $1.48{\pm}0.14$ rotifers per larva) and 1000 lx ($60{\pm}0.08%$, $1.38{\pm}0.13$ rotifers per larva). The feeding incidence of S. japonicus larvae increased with light intensity while feeding intensity showed no significant difference (P > 0.05) between light treatments.

• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.20-26
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• 2014

Objective: The low level lasers currently in the market vary in wavelength, dosage, and frequency. These devices are used with much different clinical pathology. Most notably, some studies claim that wounds heal faster with low level laser therapy due to the fact that bacteria commonly found in wounds are killed by laser light. Systemic and meta-analysis studies found the difficulty of comparison of numerous research studies because of differences in the intensities and frequencies of low level laser treatment (LLLT). The purpose of this study was to determine the effectiveness of LLLT on controlling bacterial growth. Design: Cross-sectional study. Methods: Variables included LLLT dosage and wavelength on 3 bacteria commonly seen in wounds, strains of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were used on commercially available 5.0-cm agar plates. Blue, green, and red, ultraviolet (UV) and infrared laser light sources were adjusted to either low or high intensity settings. Five Petri dishes at a time were placed directly beneath laser light sources with the exception of UV which was placed six inches below the suspended light and infrared which was placed directly on top of the Petri dish lid. Each group of five Petri dishes was irradiated for 15 minutes. Results: The results showed no effect of any of 9 different LLLT intensities or colors on bacteria growth compared to sham light. Conclusions: At least for claims of bacterial growth inhibition with LLLT, no support for this claim can be found here.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.65-75
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• 2002

The study was carried out to determine the growth and biomass production of major deciduous trees including Betula platyphylla var. japonica, Betula schmidtii, Zelkova serrata, Acer mono, Prunes sargentii, and Ligustrum obtusifolium subjected to artificial shade treatment in nursery field. The six deciduous trees seedlings grow for 2 years under different light intensity of 100%, 38-62%, 22-28%, 7-20%, and 2-6% of the full sun light intensity. The results were as follows; In the seedling heights and root collar diameters of shade intolerant species like Betula platyphylla var. japonica and Betula schmidtii, the relative growth rates of seedlings grown in full sun showed 2 times as compared with those subjected to the shade treatment of 2-6% light intensities of full sun. In the shade tolerant species like Acer mono ant Ligustrum obtusifolium, the growth performances were better in the seedlings grown in 38-62% light intensities of full sun. Total dry mass including the dry mass of leaves, shoot and root were as a whole decreased with shade treatment. The ratio of the dry mass of leaves and stem increased the dry mass of root. T/R ratio of the seedlings increased by decreasing the relative light intensity. And the T/R ratio of 2-6% light intensities of full sun was ranged from 1.1~5.0 were greater in the full sun light was ranged from 0.6~3.2. Light intensity by artificial shade treatment decreased in deciduous trees when compared on the whole, it showed tendency that SLA increases, increased that seeing resemblant tendency in LAR and LWR and changed of light intensity is strong, it increased that showed difference as statistical. But, LWR of Betula platyphylla var. japonica increased gradually and showed tendency that decreases rapidly in the shade treatment of 2-6% light intensities of full sun. This result is thought that biomass production decreased by shading treatment influenced in physiological characteristics such as leaf area and decrease of the leaf amount.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.312-318
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• 2020

BACKGROUND: Photoreversibility, a reversion of the inductive effect of a brief red light pulse by a subsequent far red light pulse, is a property of photo responses regulated by the plant photoreceptor phytochrome B. Plants use photoreceptors to sense photo signal and to adapt and modify their morphological and physiological properties. Phytochrome recognizes red light and far red light and plays an important role in regulating plant growth and development. METHODS AND RESULTS: The reversal responses of growth and fruiting characteristics were investigated to increase the yield of oriental melon (Cucumis Melo L. var. Kumsargakieuncheon) by means of controlling light quality in a plastic house. Red (R:660nm) and far red (FR:730nm) lights were subsequently irradiated on the whole stems and leaves of the oriental melon plant during growing periods, using red and far red LEDs as light sources, from 9:00 PM daily for 15 minutes. The intensities of R and FR light were 0.322-0.430 μmol m-2s-1 and 0.250-0.366 μmol m-2s-1, respectively. Compared to R light irradiation, combination of R and FR light irradiation increased the length of internode, number of axillary stems, number of female flowers, and fruit number of oriental melons. The results of treatment with R were similar to R-FR-R light irradiation in terms of length of internode, number of axillary stems, number of female flowers, and number of fruits. When FR treatment was considered, R-FR and R-FR-R-FR light irradiation had similarities in responses. These reversal responses revealed that oriental melon showed a photoreversibility of growth characteristics, flowering, and fruiting. CONCLUSION: These results suggested the possibility of phytochrome regulation of female flower formation and fruiting in oriental melon. The fruit weight of the oriental melon was the heaviest with the R light irradiation, while the number of fruits was the highest with the FR light. With the FR light irradiation, the fruit weight was not significantly higher compared to that of the control. Meanwhile, the yield of oriental melon fruits increased by 28-36% according to the intensities of the FR light due to the increases of the number of fruits.

• Journal of Microbiology and Biotechnology
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• v.24 no.8
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• pp.1034-1043
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• 2014

This study determined the effect of light intensity and photoperiod on the dry cell weight and total amount of carotenoids in four isolates of purple non-sulfur bacteria obtained from shaded and exposed microhabitats of a mangrove ecosystem in Kota Kinabalu, Sabah, Malaysia. The initial isolation of the bacteria was carried out using synthetic 112 medium under anaerobic conditions (2.5 klx) at $30{\pm}2^{\circ}C$. On the basis of colony appearance, cell morphology, gram staining, motility test, and 16S rRNA gene sequencing analyses, all four bacteria were identified as Afifella marina. One of the bacterial isolates, designated as Af. marina strain ME, which was extracted from an exposed mud habitat within the mangrove ecosystem, showed the highest yield in dry cell weight ($4.32{\pm}0.03g/l$) as well as total carotenoids ($0.783{\pm}0.002mg/g$ dry cell weight). These values were significantly higher than those for dry cell weight ($3.77{\pm}0.02g/l$) and total carotenoid content ($0.706{\pm}0.008mg/g$) produced by the isolates from shaded habitats. Further analysis of the effect of 10 levels of light intensity on the growth characteristics of Af. marina strain ME showed that the optimum production of dry cell weight and total carotenoids was achieved at different light intensities and incubation periods. The bacterium produced the highest dry cell weight of 4.98 g/l at 3 klx in 72 h incubation, but the carotenoid production of 0.783 mg/g was achieved at 2.5 klx in 48 h incubation. Subsequent analysis of the effect of photoperiod on the production of dry cell weight and total carotenoids at optimum light intensities (3 and 2.5 klx, respectively) revealed that 18 and 24 h were the optimum photoperiods for the production of dry cell weight and total carotenoids, respectively. The unique growth characteristics of the Af. marina strain ME can be exploited for biotechnology applications.