• Applied Biological Chemistry
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• v.44 no.4
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• pp.240-245
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• 2001

Suppression of nitrate accumulation in vegetables through foliar application of micronutrients was investigated. Spinach and lettuce were grown in pots under greenhouse condition. Micronutrient solutions containing Cu, Mn, Mo, and Zn were used; chitosan was added into one and the other contained chitosan oligomers. The micronutrient solutions were sprayed on the leaves at 3 and 4 weeks after transplanting of 20-day-old seedlings. Plants were harvested at 5-weeks after transplanting. Yield, contents of chlorophyll, Brix value, micronutrient, and nitrate, and nitrate reductase activity were measured. Fresh weights of lettuce and spinach were significantly increased by the foliar application of micronutrients. Contents of chlorophyll and micronutrients were higher in micronutrient-treated plants, while those of nitrate were reduced by about 10 and 14-23% in lettuce and spinach, respectively. Compared to the control plants, nitrate reductase activity was higher in plants treated with micronutrients. Results of this study indicate the effect of micronutrients on the suppression of nitrate accumulation was relatively small in comparison to the contents of nitrate in leaves of spinach and lettuce. To maximize the effect, nutrient composition in solution, application time, and frequency should be further examined, taking into consideration nitrogen level in soil and other environmental factors including light condition.

• Research in Plant Disease
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• v.22 no.3
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• pp.208-212
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• 2016

During the nursery seedlings stage at Muan in 2013, moisture and temperature conditions were favorable for the occurrence of onion downy mildew. Several fungicides were evaluated for controlling onion downy mildew at the stage of seedling. The disease incidence of the untreated control was 51.1%, which was sufficient to evaluate the fungicide efficacy for the control of onion downy mildew. Incidence at the mancozeb treatment (MAN treatment) was 4.4% and it was the highest control value of 91.4%. Incidence at the various fungicides treatment (MIX treatment) consisted of amectotradin plus dimethomorph, floupicolide plus propamocarb HCl, or dimethomorph plus pyraclostrobin was 10.0%, and the control value of the MIX treatment was 80.4%. Among the tested fungicides, amectotradin plus dimethomorph (AME plus DIM treatment) was selected and treated. Incidence of AME plus DIM treatment was 12.2%. There was statistically significant difference among the three different treatments and the untreated control. These results suggest that the application of fungicides on onion nursery seedlings was effective to control the onion downy mildew.

• Korean Journal of Organic Agriculture
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• v.20 no.3
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• pp.345-356
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• 2012

We conducted a survey of actual using conditions of farm-made liquid fertilizers by investigating their formulation types, materials, making processes, using methods and various beneficial effects on 29 farms certified by National Agricultural Products Quality Management Service to produce environment-friendly agricultural products in 2009. Most of the materials used to make liquid fertilizers are those that can be easily obtained around the farms. Molasses or black sugar are added as an energy source of microorganism. And leaf mold, bacterial cultures supplied by agricultural extension centers of local governments, and cultures of native microorganisms were used as microbial sources for fermenting effective microorganisms. Types of the farm-made liquid fertilizers were fermented liquid fertilizers, fermented plant juices, amino acid liquid fertilizers, calcium-liquid fertilizers, and phosphoric acid liquid fertilizers. Effects of liquid fertilizers used by the farms were found to promote plant growth by supplying nutrition, to accelerate blooming and flower bud formation, to enhance the quality of agricultural products such as increase of sugar contents and improvement of storing conditions, to induce resistance against diseases and insect pests, and to cause endurance to high temperature stress. Chemical properties of the liquid fertilizers collected were analyzed. As a result, pH and EC range showed differences according to kinds of the liquid fertilizers. Amount of macro-nutrients, such as nitrogen and phosphoric acid, in most of the collected liquid fertilizers, was found to be low. Even though the liquid fertilizers were made from same materials, their contents was found to be different depending on the making process.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.1
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• pp.7-15
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• 1993

Nitrogenous and non structural carbohydrate compounds in the remaining tissues of 10 weeks old alfalfa (Medicago sativa L.) grown in hydroponic culture, were analysed during 24 days of regrowth following shoot removal. The dry weights of the remaining organs were not significantly changed for 10 days following shoot removal. Compared with uncut plants, defoliation drastically depressed root growth, in particular that of taproot. During 6 days of regrowth, nitrogen contents in all remaning organs significantly decreased. Nitrogen loss in this period was pronounced in root system. Nitrogen contents in each organ after 24 days of regrowth in defoliated plant were recovered completely or exceeded initial level. Amino acid-N was the most readily available form of nitrogen while protein-N was the largest storage pool. The tap root contained about 51.0% and 33.4%, respectively, of the total starch and total ethanol-soluble sugar contents. The starch content of tap roots initially exceeded 40.7 mg. plant$^{-1}$ (day 0), and then declined to the minimum level on day 14. This result clearly showed that the tap root is the major storage site for metabolizable nitrogen (protein-N and amino acid-N) and carbohydrate(starch), and that the degradation of these researves occur much actively in the early period of regrowth.

• The Korean Journal of Mycology
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• v.42 no.3
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• pp.225-230
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• 2014

Sclerotinia sclerotiorum, a plant pathogenic fungus, can cause serious yield and quality losses in the winter lettuce field. For biological control of S. sclerotiorum, soil-born microorganisms that inhibit the mycelia growth of S. sclerotiorum and Fusarium oxysporum were isolated from diseased soil. Among the isolates, bacterial isolate, GG95, which was identified as Bacillus subtilis according to the morphological, physiological characteristics and by 16S rRNA similarity, showed the highest level of inhibitory activity. The growth conditions for B. subtilis GG95 were optimized in TSB media (pH 7) by culturing at $28^{\circ}C$ for 24 hrs. Maltose or fructose and peptone were selected as the best carbon and nitrogen sources, respectively. Greenhouse experiment was performed to test effectiveness of B. subtilis GG95 in the control sclerotinia rot. Drench application ($1{\times}10^8cfu/mL$, 3 times) of the bacterial culture broth to lettuce showed an effectiveness value of 88%, suggesting that B. subtilis GG95 would be a promising biocontrol agent for control of sclerotinia rot.

• The Korean Journal of Mycology
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• v.42 no.3
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• pp.219-224
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• 2014

A gram-negative bacterium was isolated from spent substrate of Agaricus bisporus and showed marked antagonistic activity against Pseudomonas tolaasii. The bacterium was identified as Pseudomonas azotoformans by based on the cultural, biochemical and physiological characteristics, and 16S rRNA gene sequence. The isolated bacterium was saprophytic but not parasitic nor pathogenic to cultivation mushroom. The isolated bacterium for P. tolaasii cell was not sufficient for inhibition in vitro. Control efficacy of Pseudomonas azotoformans HC5 to brown blotch of P. tolaasii was 73, 78, and 71% on A. bisporus, Flammulina velutipes, and Pleurotus ostreatus, respectively. In the future, the suppressive bacterium may be useful for development of a biocontrol system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.8
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• pp.28-34
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• 2000

Pyroelectric properties of the $Pb(Zr_{0.9}Ti_{0.1})O_3$ ceramics having the rhombohedral structure have been studied by using the dynamic measurement method. The pyroelectric responses of the $Pb(Zr_{0.9}Ti_{0.1})O_3$ ceramics are characterized in both low and high medulation frequency regions and their frequency depences are observed. In the low frequency region (2~200Hz), the change of polarization increases and shows the maximum since the reorientation rate of domains is higher than the modulation frequency. Inthe high frequency region (200~2000Hz), the pyroelectrci response decreases as the frequency increases, because the reorientation of domains is suppressed and so the change of polarization decreases. Pyroelectric coefficient, figure of merit, noise equivalent power and detectivity of the $Pb(Zr_{0.9}Ti_{0.1})O_3$ ceramics are measured as $1.6{\times}10^{-8}C/cm^2{\cdot},\;1.6{\times}10^{-11}C{\cdot}cm/J,\;2.4{\times}10^{-7}W/Hz^{1/2}\;and\;4.17{\times}10^6cm{\cdot}Hz^{1/2}/W$, respectively.

• Journal of Ginseng Research
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• v.33 no.2
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• pp.127-131
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• 2009

The plant protection rate of the marketed microbial products for ginseng cultivation was investigated against Rhizoctoina solani and Pythium sp. in a seedling pot experiment. A significant difference was found among the mean plant protection rates (Pm) of the microbial products, including Tolclofos-methyl (Rhizolex). The best microbial product, C-ISR2, showed a 33% and 33.6% net Pm (total Pm-control Pm) in the two tests against Rhizoctonia solani. In one test with a 58.6% control plot Pm, the total pm was 91.6%, indicating that plant protection can be done only with a microbial product in a well-conditioned field. The net Pm of C-ISR2 against Pythium sp. was 26.4%. The net Pm of a microbial product against a pathogen seems to be fixed. A significant negative linear correlation was found between the Pm and the coefficient of variation (CV) of the protection rate in all the three experiments. This indicates that the protection processes of control, microbial products, and chemical pesticides are in the same system. Pm was only dependent on CV, probably due to each seedling's microenvironment. In the linear correlation equation between the Pm and the CV of the microbial products and the control plot, the intercept of the vertical axis will be the theoretical Pm when CV is zero.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.137-143
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• 2010

Yuza (Citrus junos Sieb ex TANAKA) is a citrus fruit that is cultivated in northeast Asia. Citron is known for containing abundant antioxidants such as vitamin C, flavonoids, for example hesperidin and hesperetin, and terpenoids such as limononin. When mature citron is processed for tea or other beverage food products in Korea, massive amounts of seeds and pericarp are remained as waste. This study aimed to exploit the processed remnant of Citron for developing functional cosmetic applications. Ethanol extracts of Yuza seed and pericarp did not show significant radical scavenging activities measured by DPPH (2,2-diphenyl-1-picrylhydrazyl) method. But they contained significantly high phenolic compounds. Cultured human dermal fibroblasts and HaCaT keratinocytes were irradiated with 25 mJ UVB and the citron extracts were added to the medium of each culture. Cellular damages caused by UVB irradiation were prevented by the addition of the Yuza extract. In addition, the reduction of the enhanced MMP-1 expression after irradiation of UVB in human dermal fibroblasts was observed. Also the increased level of pro-inflammtory TNF-$\alpha$ in the UVB irradiated HaCaT cells was decreased. The collagen expression was enhanced by the extract. Yuza extract markedly inhibited melanin production from $\alpha$-MSH treated B16F1 melanoma cells. Melanin assay, tyrosinase zymography results indicated that Yuza extract had strong depigmenting activity. In conclusion, Yuza ethanol extracts have good anti-photoaging and strong anti-melanogenic efficacies.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.319-324
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• 2008

The sweet pepper (paprika) is one of the most important exported vegetable crops in Korea. This study evaluated the storability of sweet pepper fruits between 2 cultivars with different maturities under different storage conditions. The sweet peppers ('Special' and 'Fiesta') were grown in a rockwool hydroponic system, and harvested two different maturities: half-maturity and full-maturity levels. The sweet pepper fruits were stored in MA(non-ventilated) and non-MA(ventilated) conditions at 4 and $9^{\circ}C$ for 20 days. The storability of sweet pepper fruit was the highest in $4^{\circ}C$ MA conditions that remained 5% carbon dioxide and 10% oxygen during the storage. The ethylene concentration in MA condition showed $2{\sim}8{\mu}l/l$ regardless of storage temperatures, cultivars and maturities. The fruits packaged with non-ventilated film, showed lower weight loss, and higher firmness, and there was no different about decay ratio compared to the fruits packed ventilated film. The coloration of semi-matured fruit that colored 50% before storage progressed faster in non-ventilated packaging condition at $9^{\circ}C$, but their color did not changed as same as level of full-matured fruit. The electrolyte leakages and respiratory rate that estimated degree of chilling injury was highest in non-MA(ventilated) conditions of 'Special' full matured fruit placed at room temperature for 3 days following storage at $4^{\circ}C$ for 20 days. It may be suggested that sweet pepper fruit packed sealed (non-ventilated) film and stored at non-chilling temperature can be maintained better quality for long term storage.