• Journal of Life Science
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• v.16 no.3 s.76
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• pp.522-526
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• 2006

To investigate the effects of UV-B on fatty acid composition, lipid peroxidation and biochemical defense responses of plant, kidney bean (Phaseolus vulgaris L.) was subjected to enhanced UV-B irradiation [daily dose : 0.02.(No UV-B) and 11.36 (enhanced UV-B) $kJ\;m^{-2};UV-B_{BE}$] for 3 weeks. UV-B drastically inhibited both height and dry weight of kidney bean. The content of malondialdehyde significantly increased by about 50% after 3 weeks of UV-B irradiation. The ratio of unsaturated to saturated fatty acids of kidney bean was increased by UV-B irradiation. Three major polyamines of kidney bean leaves : putrescine, spermidine and spermine, were observed. All of the polyamine contents were increased with UV-B irradiation. These results suggested that enhanced UV-B radiation caused oxidative stress on lipids and biochemical protection responses might be activated to prevent from damaging effects of oxidative stress generated by UV-B irradiation.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.635-642
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• 1996

Rice plants, cv. Koshihikari, were subjected to the biologically effective ultraviolet-B(UV-BBE) radiation {daily dose : 0.0 (control) and 11.5 (enhanced UV-B) KJ m-2} to investigate the effect of enhanced UV-B radiation on lipid peroxidation and to determine whether carotenoids and polyamines are involved in protection mechanism against enhanced UV-B radiation. Enhanced UV-B radiation significantly depressed plant dW weight. Malondialdehyde (MDA) content in rice leaves was increased by about 30% after 6 days of UV-B irradiation. Total carotenoid contents tended to slightly decrease with the UV-B irradiation, even though there was no significance. In rice leaves, 3 major polyamines, putrescine, spermidine and spermine are observed. All of the polyamine contents were increased with UV-B irradiation. The results suggest that enhanced UV- B radiation caused oxidative stress on lipids and that polyamines may serve as a biochemiral protectant against increased UV-B radiation in rice plants.

• Journal of Life Science
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• v.8 no.3
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• pp.272-278
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• 1998

To investigate the effects of different UV-B levels on plant growth, cucumber plants were subjected to three levels of biologically effective ultraviolet-B(UV--$B^{BE}$ radiation [daily dose : 0.03(No UV-B), 6.40(Low UV-B) and 11.30 (High UV-B) kJ $m^{-2}$, UV--$B^{BE}$] in the growth chambers for 3 weeks during the early growth period. High and low levels of UV-B irradiation drastically decreased both dry weight and leaf area, but increased specific leaf weight of cucumber. Plants subjected to UV-B resulted in 30% and 20% reduction of photosynthesis rate by high and low UV-B, respectively. However, respiration rate was not affected by the UV-B. With increasing UV-B intensity, total chlorophyll contents were decreased linearly, while the contents of flavonoid were increased linearly. These results suggest that the present levels of UV-B may affect the growth of cucumber plant compared with a UV-B-free condition. It is likely that the growth of cucumber will be affected by enhanced UV-B due to ozone depletion in the near future.

• Korean Journal of Environmental Agriculture
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• v.16 no.3
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• pp.227-232
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• 1997

Visible injury appeared 7 days after ultraviolet-B(UV-B) irradiation, but did not show any significant decline of growth in cucumber plant. However the growth of the first leaves of fertilized plants was suppressed by UV-B irradiation. Especially the most effective growth retardiation appeared when supplied with nitrogen rather than phosphate and potassium. These results suggest that UV-B may play an important role in inhibiting nitrogen metabolism. Therefore we examined the effect of activity of nitrate reductase, and found that the nitrate reductase activity of the first leaves was increased by UV-B irradiation for 7 days and fertilization. We examined the effect of plant hormone on the inhibition of growth in the first leaves. Benzyladenine promoted the growth of discs excised from the first leaves by fertilization and without UV-B, but did not promote the growth of leaf discs from UV-B irradiated plants. We conclude that the UV-B-induced decrease in the growth of the first leaves could be related to reduction in sensitivity to plant hormones.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.135-142
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• 2010

To investigate the effects of ultraviolet(UV-B) on growth and biochemical defense responses of plant, garden balsam (Impatiens balsamina L.) was subjected to enhanced UV-B irradiation [daily dose: 0.02 (No UV-B) and 11.34 (enhanced UV-B) kJ $m^{-2}$ ; $UV-B_{BE}$] for 3 weeks. Enhanced UV-B drastically inhibited leaf area as well as dry weight of garden balsam. The content of malondialdehyde was significantly increased by about 50% after 3 weeks of UV-B irradiation. The ratios of dehydroascorbate/ascorbate and oxidized glutathione/reduced glutathione were also considerably increased by UV-B irradiation. Three major polyamines of garden balsam leaves: putrescine, spermidine and spermine were observed. All polyamine contents were increased with UV-B irradiation. The enzyme (superoxide dismutase, ascorbate peroxidase etc.) activities of garden balsam were increased by the UV-B enhancement. Based on the results, enhanced UV-B caused oxidative stress in garden balsam and biochemical protection responses might be activated to prevent from damaging effects of oxidative stress generated by UV-B irradiation.

• Journal of Korea Foresty Energy
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• v.19 no.1
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• pp.1-6
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• 2000

This study was carried out to investigate the growth responses of Pinus densiflora seedlings to enhanced UV-B environment for 16 weeks in the field condition. The seedlings were treated with one of three levels of UV-B dosages - ambient UV-B, ambient + 3.2, and ambient + 5.2 KJ m$^{-2}$day$^{-1}$ and the irradiation was performed at the stage before the germination, the fully expanded cotyledon, and the primary needles grown more than 0.8cm in length of the seedlings, respectively. Enhanced UV-B irradiation reduced the height and the root collar diameter growth, and dry mass production of the seedling, and T/R ratio was increased by the UV-B treatment. Difference in seedling growth was observed by difference in time of the UV-B treatment. Among the seedlings which were treated with ambient - 3.2 KJ m$^{-2}$day$^{-1}$, height and root collar diameter growth was relatively high in the seedling received the UV-B treatment at the stage before the germination. The lowest dry mass production was observed in the seedlings received the UV-B at stage of cotyledon both in two levels of enhanced UV-B treatment. Chlorophyll concentration was reduced by enhanced UV-B irradiation, and chlorophyll a/b ratio was increased by the UV-B treatment.

• Journal of Mushroom
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• v.19 no.4
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• pp.329-335
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• 2021

This experiment was conducted to investigate the changes in freshness parameters and determine the optimal UV-B irradiation conditions for each storage period for Heuktari, an oyster mushroom cultivar, grown under LED lightNo significant changes were observed in the CO₂ and O₂ content until day 12 of storage; however, after day 15, the CO₂/O₂ ratios were higher in the UV-treated groups than in the untreated groups. No color difference was observed between the UV-treated and untreated groups. In all UV-treated groups, hardness decreased over time; however, the group irradiated for 15 minutes showed higher hardness values than those of the untreated group. The UV-irradiated group showed higher ergosterol content than did the untreated group, and scanning electron microscopy revealed that mushroom cell wall destruction increased with increased UV treatment time. Overall, these findings confirmed that UV-B irradiation increased the ergosterol content of Heuktari but decreased its freshness and negatively impacted other storage characteristics.

• Journal of Bio-Environment Control
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• v.12 no.4
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• pp.252-258
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• 2003

This experiment was performed to investigate the effect of UV-B (4 kJ${\cdot}m^{-2}{\cdot}d^{-1}$) irradiation and growth inhibitor (50 mg${\cdot}L^{-1}$ diniconazole, 500 mg${\cdot}L^{-1}$) treatment on the overgrowth retardation and the growth and yield afterplanting in plug-grown cucumber, tomato, and hot pepper sedlings. Stem length of UV-B-irradiated and iniconazole-treated seedlings was shortened by 38 and 35%^ in cucumber, 37 and 41% in tomato, and 23 and 23% in hot pepper, respectively, compared with non-treated seedlings. While retarding effect ofhexaconazole waslower that that of UV-B or diniconazle. Leaf area and dry weight alson decreased but ldaf thickness increased in UV-B irradiated or growth-inhibitor-treated seedlings. Even thouth the plant height and leaf area of UV-B-irradiated seedlings ant seedling stage were shorter and smaller that those ofnon-treatedd seedlings, they were recovered to the similar level to the growth of non-treated seedlings 20to 30days after trasplantin. The diconazole-and hexaconazole-treated seedlings were delayed recovery to their normal growth, Fruit yiedl of UV-V-irradiated hot pepper and tomato slightly increased but UV-B irradiated cucumer had similar yield to growth-inhibitor-treated one. It suggested that the use of UV-B irradiation could become a reliable tool of overgrowth retardation of plug-grown vegetable seedlings in greenhouse.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.309-313
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• 2000

To investigate the effects of different UV-B levels on growth and biochemical defense response in plants, cucumber plants were subjected to three levels of biologically effective ultraviolet-B $(UV-B_{BE})$ radiation [daily dose: 0.03 (No), 6.40 (Low) and $11.30\;(High)\;kJ{\cdot}m^{-2}$, $UV-B_{BE}$] in the growth chambers for 3 weeks during the early growth period. Enhanced UV-B radiation drastically decreased both dry weight and leaf area of cucumber. With increasing UV-B intensity, chlorophyll content was decreased, however the level of malondialdehyde was highly increased linearly. Total contents of ascorbic acid and glutathione were tended to increase by UV-B, while the ratios of dehydroascorbate/ascorbate and oxidized glutathione/reduced glutathione were significantly increased with increasing UV-B intensity in cucumber. All the enzyme activities investigated (superoxide dismutase, ascorbate peroxidase, dehydroascorbate reductase, guaiacol peroxidase etc.) in cucumber were increased by the UV-B enhancement. These results suggested that enhanced UV-B irradiation caused photooxidative stress in cucumber plant and resulted in significant reduction in plant growth. Biochemical protection responses might be activated to prevent the leaves from damaging effects of oxidative stress generated by UV-B irradiation.

• Food Science and Preservation
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• v.16 no.3
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• pp.454-458
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• 2009

The effect of UV-C irradiation on microbial growth and quality of red pepper powder during storage was examined. Red pepper powder was irradiated with doses of 27, 54, or $108\;kJ/m^2$ and stored at $20^{\circ}C$ for 4 weeks. UV-C treatment of red pepper powder decreased the populations of total aerobic bacteria and Bacillus cereus in proportion to radiation dose. In particular, total aerobic bacteria and B. cereus populations decreased by 1.03 and 0.90 log CFU/g after irradiation at $108\;kJ/m^2$, respectively, compared with control values. UV-C irradiation caused negligible changes in the Hunter color L, a, or b values. Sensory quality results on red pepper powder were not significantly different between treatments. Therefore, UV-C irradiation can be used to inhibit microbial growth in red pepper powder, without impairing quality during storage.