• Journal of Life Science
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• v.17 no.6 s.86
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• pp.756-761
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• 2007

Cenus Malus is a long-lived woody species primarily distributed throughout Asia. Many species of this genus are regarded as agriculturally and ecologically important. The phynetics and genetic diversity among eight species of genus Malus were reconstructed using the random amplified polymorphic DNA (RAPD) markers. In a simple measure of intraspecies variability by the percentage of polymorphic bands, the M. micromalus exhibited the lowest variation (34.7%). The M. pumila showed the highest (50.0%). Mean number of alleles per locus (A) ranged from 1.347 to 1.500 with a mean of 1.437. The phenotypic frequency of each band was calculated and used in estimating genetic diversify (H) within species. The mean of H was 0.190 across species, varying from 0.155 to 0.220. In particular, two cultivated species, M. pumila and M. asiatica, had high expected diversity, 0.314 and 0.307, respectively. On a per locus basis, the proportion of total genetic variation due to differences among species ranged from 0.388 to 0.472 with a mean of 0.423, indicating that 42.3% of the total variation was found among species. The phylogenetic tree showed three distinct elates. One includes M. sieversii, M. pumila, and M. asiatica. Another includes three M. baccata taxa. The other includes M. sieboldii, M. floribunsa, and M. micromalus. One variety and one form of M. sieboldii were well separated each other. RAPD markers are useful in germ-plasm classification of genus Malus and evolutionary studies.

• Korean Journal of Plant Resources
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• v.9 no.2
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• pp.105-112
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• 1996

Physicochemical properties of Youngia sonchifolia were compared according to harvesting time and brine methods for its Kimchi preparation. Moisture contents in the roots and the leaves of Y. sonchifolia grown for 5 weeks was more than those grown for 11 weeks. 5-week-grown Y. sonchifolia contained more total free sugar than 11-week-grown ones, and among total free sugar the content of fructose was the most, and the contents of glucose and sucrose were rather high. The roots of 11-week-grown Youngia sonchifolia were harder than those of 5-week grown ones. When the roots were soaked in NaCl solution, the hardness decreased with time. Salt concentration of the Kimchi of Y. sonchifolia increased by the brined material of the Kimchi with soaking time.Salt concentration of the Kimchi was higher in the leaves than in the roots.The roots and leaves of Y.sonchifolia grown for 11 weeks contained organic acids such as malic acid, oxalic acid, succinic acid,lactic acid, and citric acid,among which major organic acids were malic acid, oxalic acid, succinic acid, whereas lactic acid and citric acid were minor organic acids.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.4
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• pp.199-213
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• 2008

Saemangeum salt-water Lake has been created by the completion of the sea-dike in April 2006. To monitor the water qualities of the lake during the sea-dike construction, salinity, SS, nutrients(DIN, DIP, DISi), and chlorophyll-$\alpha$ was analyzed for the surface water from 1999 to 2007. Due to the dike construction, weaker tidal current and lesser resuspension of bottom sediment resulted in the marked decrease of the concentrations of SS in the lake water. Consequently the clearer lake water has provided better condition for primary production with deeper penetration of sunlight into the water column and sufficient nutrient content in the water. Finally the chlorophyll-$\alpha$ content became approximately double in the concentration after the dike construction. Highly stimulated algal production with the marked decrease of the concentrations of SS was decreased the concentration of DIP in the surface water. On the other hand the concentration of DIN and DISi in surface water was increased after dike construction due to the expansion of the freshwater and the supply from bottom layer. As a result, the lake revealed an extremely high NIP ratio and a DIP-limited ecosystem. The lake has been transformed from a typical coastal ecosystem to a brackish one. Since the dike completion, the lake has shown a similar change pattern to the Geum River estuary. Due to the salt-wedge intrusion of seawater, it is highly probable to expect the formation of low-oxygen zone at the bottom layer near the river-mouth area of the lake during the summer. Therefore we need a continuous sentinel monitoring of bottom water qualities in the near future.

• Korean Journal of Environmental Agriculture
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• v.21 no.4
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• pp.255-260
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• 2002

This study was conducted to evaluate the effect of the proper application level of anaerobic digestion waste water on rice. The waste water was from methane fermentation of pig manure to use as a liquid manure. The mixture treatment of 70% liquid manure and 30% chemical fertilizer (LM 70%+CF 30%) and 100% liquid manure (LM 100%) treatment were higher number of tiller than other treatments at the both tillering and heading stages of rice. The yields of LM 70%+CF 30% and LM 100% treatments were a little higher than that of NPK treatment, but the mixture treatment of 50% liquid manure and 50% chemical fertilizer (LM 50%+CF 50%) was a little lower yield than NPK treatment. The periodic changes of the $NH_4-N$ and $NO_3-N$ contents of the NPK and the LM 50%+CF 50% treatments in paddy soil were a little higher than those of other treatments at the early stage of rice. The $NH_4-N$ contents of NPK and the LM 50%+CF 50% treatments in irrigation water quality were higher than those of other treatments, however there was no difference in $NO_3-N$ content among the treatments. The $NH_4-N$ and $NO_3-N$ contents of non fertilizer treatment in infiltration water quality were leached a little higher than those of other treatments. It may be due to poor growth of rice following to reduce the nutrient uptake by rice and to increase relatively the nutrient leaching to the ground water. The proper application level of anaerobic digestion waste water as a liquid manure could be suggested to apply LM 70%+CF 30%. All treatments were the same amount of nitrogen content for the standard application amount on rice.

• Korean Journal of Environmental Agriculture
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• v.9 no.2
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• pp.133-141
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• 1990

For the purpose of evaluating nutrient loadings into rivers and lakes from agricultural land, especially from paddy fields and also nutrient degradation in drainage channels, the Total Kjeldahl Nitrogen(TKN) and the Total Phosphorus(TP) were investigated in 29.5 ha. paddy fields in Hwa-Sung, Kyong-Ki, Korea, during the period from May 8, 1989 to Sep. 27, 1989. The results of the study can be su㎜arized as follows : 1. Annual inputs into paddy fields were 180 N-kg/ha 46 P-kg/ha. by fertilization, and 15.0 TKN-kg/ha. 10.0 TP-kg/ha. by irrigation, 8.0 TKN-kg/ha. 0.34 TP-kg/ha. by rainfall respectively. The amount of nutrient involved in surface runoff from paddies was 39.0 TKN-kg/ha. 9.2 TP-kg/ha. and in seepage 7.5 TKN-kg/ha. 2.1 TP-kg/ha. respectively 2. In WS1 stream(reach length equals 950m), nutrients decreased 0.31 TKN-mg/L/km, 0.01 TP-mg/L/km and in WS2 stream (reach length equals 750m) which are more meandering and undulating than WS1, the nutrients decreased 0.84 TKN-mg/L/km, 0.11 TP-mg/L/km. From these results, it was concluded that low stream velocity due to meandering and undulation promotes more degradation of nutrient concentrations. 3. For the purpose of decreasing nutrient loads from paddy fields, the amount of fertilizer used needs to be controlled, irrigation weirs need to be constructed in the drainage channels to delay the transportation of nutrients by decelerating the stream velocity and plants such as plantain-lily need to be cultivated in the channel to consume nutrients and therefore enlarge chances of self-purification.

• The Korean Journal of Pesticide Science
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• v.17 no.1
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• pp.33-40
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• 2013

Pyrifluquinazon is known to act as a feeding inhibitor in several insect species. In this study, we investigated the effect of pyrifluquinazon on the whiteflies, Trialeurodes vaporariorum and Bemisia tabaci. Pyrifluquinazon showed high insecticidal activity (> 90%) against adult T. vaporariorum and B. tabaci at 12.5 ppm to 50 ppm. However, there was no effect on eggs and nymphs of both species. Pyrifluquinazon showed low insecticidal activity in root and foliar uptake. Control efficacy of pyrifluquinazon was above 90% at 5 days after treatment. In order to investigate the behavioral response of the whiteflies initiated by application of pyrifluquinazon, we tested the contact toxicity and ingestion toxicity. After 1 h of contact, whitefly drop, wing convulsion, and paralysis were observed. Similar phenomenon of whitefly population was observed in test of ingestion toxicity after 3 h. In the choice test, pyrifluquinazon showed repellent activity against both species. These results suggest that pyrifluquinazon cause behavioral disorder rather than direct inhibition of feeding.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.1
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• pp.20-28
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• 1999

Nine soil media when placed over a plastic sheet with three seeding rates were evaluated for influence on covering rate, height, growth, surface hardness, tear strength and sod establishment of Kentucky bluegrass. 1. Bark, peat and vermiculite over a plastic sheet had good effect in terms of the establishment of Kentucky bluegrass sod. 2. The good establishment of Kentucky bluegrass sod grown on bark, peat and vermiculite over a plastic sheet seemed to be caused by physical and chemical properties of each soil medium. 3. Sand, sandy loam, perlite and peatmoss caused poor effects on the covering rate, the growth, and the tear strength of Kentucky bluegrass. 4. Optimum seeding rate was $10g/m^2$ in terms of density and competition. 5. Good quality sod more depended on soil media than on seeding rates in this study.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.543-553
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• 2013

In Korea, there have been many studies and progresses on various types of pilot scale or commercialized field scale Best Management Practices(BMP) during the last 10 years. Runoff characteristics of diffuse pollutants from different land uses are well identified and documented. However, for the coastal area connected directly with shoreline, runoff patterns and management schemes of non-point pollution were not fully studied. Recently, coastal area is emerging as a new development axis especially in west coast side of Korea such as Incheon city and Chungnam province, thus urbanized area rapidly increased but there are no buffer zones and BMP facilities to aim at preventing direct discharge of the first flush into coastal sea and beaches. In this study, parking area in Deacheon harbor, Boryeong City in Chungnam Province was selected and rainfall runoff was monitored for two year period in order to examine run-off features from which proper type of BMP suitable for coastal area is proposed. Coastal area usually has a low ground water level and consists of plain land, so that large scale BMP such as storm water retention pond and wetland requiring great excavation works is not best management plan. In addition, monitoring study shows that storm water from the paved parking area has a high salinity compared with those in storm water from the inland. High salinity is detrimental for the vegetation. Therefore, BMP employing least vegetative cover and also in terms of maintenance is a good option such as infiltration trench and porous pavement.

• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.32-38
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• 1999

A Saprolegnia sp. was isolated from cultured snakehead, Channa argus, and its physiological characteristics were investigated. The optimum temperature, pH and NaCl concentration for mycelial growth of Saprolegnia sp. were $25^{\circ}C$, 6.0 and 0%, respectively. The mycelial growth was increased with the addition of 10 mM phosphate and 10mg/L casamino acid. The essential oils extracted from three plants, Artemisia princeps var. orientalis, Thuja orientalis and Chamaecyparis obtusa have been tested to know whether they inhibit the growth of Saprolegnia sp. at six different oil concentrations(10, 100, 500, 1,000, 1,500 and 2,000 ppm). Essential oil from A. princeps var. orientalis began to inhibite the mycelial growth of Saprolegnia sp. at the concentration more than 10ppm. Using other essential oils from T. orientalis and C. obtusa, those initially inhibited the mycelial growth of Saprolegnia sp. at the concentration over 10 ppm and complate inhibition of mycelial growth was observed at over 500 ppm. The histopathological features of Snakehead infected by Saprolegnia sp. were studied. A club shape of gill lamella epithelial cells was observed in the gill. The mycelial cells were penetrated into muscular tissue, and the accumulation of the ceroid was observed in the liver, spleen and kideny tissue in common. The necrosis of tubular epithelial cells was seen in the liver tissue, parenchymal tissue in the spleen and tubular epithelial cells in the kidney.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.280-287
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• 2004

We investigated the residual amounts of endosulfan and procymidone taken by vegetables grown in hydroponics culture and field conditions treated with the pesticides in order to evaluate safe cultivation concentration of the pesticides in the vegetables. Endosulfan and procymidone were selected as test pesticides because they have been reported to frequently detect in agricultural products at different concentrations. In hydroponic culture, by Chinese cabbage, procymidone was absorbed 3.8 times higher than endosulfan. The higher the pesticide concentration get, the worse the plant grew. In soil treated with 10 mg/kg of endosulfan, the pesticide absorbed by Leafy radish, Chinese cabbage and radish was less then their MRLs. In case of carlot, the residue level in soil which did not exceed its MRL was 1 mg/kg. The concentrations of procymidone in soil which did not exceed the MRLs in Leafy radish, Chinese cabbage, radish and carrot were 10, 10, 2 and 1 mg/kg, respectively Usually aged endosulfan and procymidone residues were less absorbed into crops than the fresh ones. Chinese cabbage absorbed more endosulfan and pocymidone than leafy radish, radish doing more than carrot.