• Korean Journal of Environmental Agriculture
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• v.25 no.2
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• pp.147-156
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• 2006

This study was conducted to investigate natural distribution of aquatic plane and to find out natural aquatic plants which highly absorb nutrient N and P. We surveyed vegetation within ${\pm}2m$ from streamside in 12 tributaries of the West Nakdong river watershed during May to October in 2003. Hydrophytes surveyed in tributaries of the West Nakdong river watershed were 27 families, 61 genera, 76 species, 3 varieties. Major dominance species of aquatic plants were Z. latifolia, P. communis, P. thunbergii, P. arundinacea, P. japonica, and P. distichum var. indutum. Aquatic plants having high production ability of biomass were Z. latifolia, P. communis, P. arundinacea, P. japonica, and E. crus-galli var. echinata. In the vertical distribution of hydrophytes within streams, dominant species were P. thunbergii and P. japonica in the upper stream, but dominant species in the downstream were P. communis and Z. latifolia. Species diversity or aquatic, plants was reduced, but their biomass and nutrient (T-N and T-P) content per the natural area unit $(m^2)$ were increased in the downsteaam. Nutrient N and P content of aquatic plants per the natural area unit were high at Joman river, Pyeonggangcheon, Bulam drainage canal, and Hogyecheon. Fifty-seven species of aquatic plants having high biomass were grounped into 4 categories $(I{\sim}IV)$ according to their nutrient content per dry weight unit. I group $(T-N,\;\geqq20gkg^{-1}\;&\;P_2O_5,\;\geqq7gkg^{-1})$ was comprised of 3 submerged plants (H. verticillata, P. crispus, and C. demersum), e emergent plants (O. javanica, P. distichum var. indutum, and R. sceleratus), 1 suspended plant (T. japonica), and 1 riparian plant (A. lobatum). Otherwise, in classification of natural hydrophytes according to their nutrient content per natural area unit, Z. latifolia, P. communis, P. longiseta, P. arundinacea, and P. distichum var. indutum possessing great biomass productivity as emergent plants were included in I group $(T-N,\;\geqq1gm^{-2}\;&\;P_2O_5,\;\geqq0.7gm^{-2})$.

• Korean Journal of Environmental Agriculture
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• v.25 no.2
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• pp.138-146
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• 2006

To understand the status of water quality and work out a suitable countermeasures in Seonakdong watershed which has poor agro- environmental condition because of severe point and non-point source pollution by popularized city and near sea, we investigated the pollution sources and water quality from '03 and '05 and the result were mapped with GIS and RS for end-users's convenient comprehense and conjunction of water quality and geological data. The most degraded tributary was Hogeo stream which was affected directly by highly popularized Gimhae city, the main pollution source of the watershed. The pollution of tributaries in watershed increased the T-N of main body that reached over 4 mg/L during dry season. Pyeonggang stream and the lower part of main water way were suffered from high salt contents induced near sea and the EC value of those area were increased to 2.25 dS/m. The delivered loads of T-N and T-P were largest in Joman river as 56% and 61% of total delivered loads 1mm tributaries because of lots of stream flow. When Management mandate for irrigation water in Seonakdong river watershed was mapped for estimating integrated water quality as the basis of classification of EC and T-N contents in water, Hogeo and Shineo catchments were showed the requiring countermeasures none against nutrients hazard and Pyeonggang catchment was the vulnerable zone against nutrients and salts hazard. As the result, Seonakdong watershed had very various status of water quality by characteristics of catchments and countermeasures for improving water quality and crop productivity safely should changed depend on that.

• Korean Journal of Environmental Agriculture
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• v.25 no.2
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• pp.164-169
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• 2006

This study was conducted for 10 days from 17 July to 26 July in 2005 to measure the amount of xylem sap flow under short-term variation of soil moisture regimes at -20 kPa, -50 kPa and -80 kPa in eight-year-old 'Fuji'/M.9 apple trees with different fruit loads. Fruit load was adjusted as three different treatments with standard (100%), 1/2 times (50%) and 2 times (200%) on the basis of optimum fruiting number per tree as the standard fruit load of Fuji cultivar. Trees with standard fruit load during the experimental period showed higher xylem sap flow at -50 kPa of soil moisture regimes than those of trees with 1/2 times and 2 times fruit load. Trees with 1/2 times and 2 times fruit load had similar patterns of the diurnal changes of xylem sap flow, vapor pressure deficit (VPD), and maximum evapotranspiration (ETm). However, trees with 2 times fruit load at -50 kPa and -80 kPa of soil moisture regimes produced lower amount of xylem sap flow than ETm. Trees with standard fruit load produced $1.06{\sim}3.93$ L/tree more amount of xylem sap flow than ETm at all soil moisture regimes. But xylem sap flow of tees with 2 times fruit load had 21% lower at -50 kPa and $31{\sim}36%$ lower at -20 kPa and -80 kPa of soil moisture regimes, respectively than that of trees with standard fruit load. Shoot growth and leaf area were significantly the highest in trees with standard fruit load while those of trees with 2 times fruit load recorded significantly lowest. Leaf water potential of trees with standard fruit load was lower than that of trees with 1/2 times and 2 times fruit load. It indicated that tees with standard fruit load had higher water use for transpiration than other treatments and tees with 2 times fruit load received more stress for the transpiration process under low soil moisture regimes. Consequently, 'Fuji'/M.9 apple trees, the fruit load and soil moisture should be maintained optimum to increase xylem sap flow and transpiration during higher growth period.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.122-128
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• 2012

BACKGROUND: Mine drainage from metal mining districts is a well-recognized source of environmental contamination. Oxidation of metal sulfides in mines, mine dumps and tailing impoundments produces acidic, metal-rich waters that can contaminate the local surface water and soil. METHODS AND RESULTS: This experiment was carried out to investigate the pollution assessment of heavy metal on the water quality of mine drainage, paddy soils and sediment in lower watershed affected by mine drainage of the Sambo mine. The average concentrations of dissolved Cd (0.018~0.035 mg/L) in mine drainage discharged from the main waste rock dumps(WRD) was higher than the water quality standards (0.01 mg/L) for agricultural water in Korea. Also, the average concentrations of dissolved Zn, Fe and Mn were higher than those of recommended maximum concentrations (Zn 2.0, Fe 5.0, Mn 0.2 mg/L) of trace metal in irrigation water proposed by FAO (1994). The average contents of Pb and Zn in paddy soils was higher than those of standard level for soil contamination(Pb 200, Zn 300 mg/kg) in agricultural soil by Soil Environmental Conservation Act in Korea. Also, the concentrations of Cd, Pb and Zn in sediment were higher than those of standard level for soil contamination (Cd 10, Pb 400, Zn 600 mg/L) in waterway soil by Soil Environmental Conservation Act in Korea. The enrichment factor (EFc) of heavy metals in stream sediments were in the order as Cd>Pb>Zn> As>Cu>Cr>Ni. Also, the geoaccumulation index (Igeo) of heavy metals in stream sediments were in the order as Zn>Cd>Pb>Cu>As>Cr>Ni, specially, the geoaccumulation index (Igeo) of Zn (Igeo 3.1~6.2) were relatively higher than that of other metals in sediment. CONCLUSION(s): The results indicate that stream water and sediment were affected by mine drainage discharged from the Sambo mine at least to a distance of 1 km downstream (SN-1, SN-2) of the mine water discharge point.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.328-335
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• 2010

This study was conducted to determine effects of soil pH and form of nitrogen fertilizers on tomato growth and chemical properties of greenhouse soil using ferigation system. Tomato (Lycopersicon esculentum Mill. cv. Superdoterang) were grown for three months in 18 L pots filled with two soil (pH 6.8 and pH 8.7). 4 different nitrogen fertilizers (urea, ammonium nitrate, ammonium sulfate, and potassium nitrate) were fertigated with different concentrations of 0, 10, 50, and 100 mg N/L during tomato cultivation. Soil pH 8.7 decreased yield and chlorophyll fluorescence compared with soil pH 6.8. Yield at soil pH 8.7 increased by ammonium nitrate and ammonium sulfate fertigation. Soil pH 6.8 induced increment of yield by nitrogen concentration than form of nitrogen fertilizers. Soil pH after cultivation of tomato decreased by application of ammonium nitrate and ammonium sulfate. Soil EC by 100 mg N/L application of ammonium sulfate was twice as much as other fertilizers. Form of nitrogen fertilizer had less effect on concentration of soil $NH_4^+$-N and $NO_3^-$-N in soil but the concentrations slightly reduced at pH 8.7. These results indicate that application of urea and ammonium nitrate for a nitrogen source of fertigation has little affects on soil chemical properties before and after tomato cultivation.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.328-336
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• 2008

Metal mining district drainage is a well recognized source of environmental contamination. Oxidation of metal sulfides produces acidic and metal-rich waters that contaminate local surface water and ground water in mines, mine dumps, and tailing impoundments. This monitoring study was carried out to investigate the stream water quality and pollution as affected by the Sambo mine drainage in relation to the relative distance from the mine. It obvious that pH values of the mine drainage ranged from 5.8 to 6.9, while the average concentrations of the dissolved chemical constituents for EC, $SO_4^{2-}$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were $1.77\;dS\;m^{-1}$, 929, 14.6, 263.3, and 46.9 mg/L in mine drainage discharged from the main waste rock dumps (WRD), respectively. Furthermore, EC values and sulfate concentrations exceeded the critical toxicity levels in agricultural water for rice plant ($1.0\;dS\;m^{-1}$ for EC and 54.0 mg/L for $SO_4^{2-}$). Also, the average of dissolved cadmium concentrations ($0.016{\sim}0.021\;mg/L$) was higher than water quality standard (0.01 mg/L) for agricultural water in Korea, in addition to Zn, Fe and Mn were higher than trace metals maximum concentrations which recommended by FAO for irrigation water. The results indicate that mine drainage discharged from the Sambo mine affected stream water at least to distance of 1 km downstream of the mine water discharge point. EC values, $SO_4^{2-}$ and $Ca^{2+}$ concentrations in discharged water positively correlated with dissolved Cd, Zn, Al and Mn concentrations, while the pH values negatively correlated. In addition, EC values, $SO_4^{2-}$ and $Ca^{2+}$ concentrations were negatively correlated with pH values.

• Applied Microscopy
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• v.36 no.3
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• pp.173-182
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• 2006

Recently, the pomegranate seed oil (PSO) has been reported to have various efforts including anti-cancer effect. In this study, we examined the liver-protecting effect of the PSO on the hepatotoxicity induced by $CCl_4$ using the BALB/c mice. The PSO was made from dried seeds of black pomegranate (Punica grantum) by heating and squeezing. The expreimental animals were divided into 3 groups; control group treated with olive oil only, experimental group 1 treated with $CCl_4$ only, and experimental group 2 treated with PSO and $CCl_4$. 24 hours after injection of $CCl_4$ into the peritoneal cavity, we collected the blood samples to measure the level of serological factors; aspartate aminotransferase(AST), alanine aminotransferase (ALT), total protein, albumin, total bilirubin, direct bilirubin and alkaline phosphatase. Simultaneously we observed the histological change of liver under the light and electron microscope. As the result, AST and ALT showed $88.7{\pm}14.9IU/L\;and\;22.0{\pm}3.12IU/L$ in the control group, $1963.7{\pm}1212.9IU/L\;and\;4495.4{\pm}2803.6IU/L$ in the experimental group 1, and $432.2{\pm}260.1IU/L\;and\;692.3{\pm}433.1IU/L$ in the experimental group 2. The experimental group 2 showed significant difference as compared with experimental group 1 (P<0.005). In histological study, the experimental group 2 was recovered than experimental group 1 which had abnormal mitochondria, increase of lysosomes, and severe necrosis at the central vein zones. These results indicated that the PSO had the liver protecting effect. However, The further study on the relationship between ingredients of pomegranate seed and liver protecting effect is in need.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.30-36
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• 2012

This study was conducted to evaluate the microbiological hazard on nursery school children's hands and to investigate the reduction effect of hand washing education. A total of 59 nursery school children's hands were tested. The average number of total aerobic bacteria was $3.72{\pm}0.38log\;CFU/hand$. Five children's hands(2 male and 3 female) were positive(14.3%) for the coliform bacteria. These results showed that hand washing education are required repetitively. Among the pathogenic bacteria tested in this study, $Staphylococcus$ aureus and $Bacillus$ $cereus$ were detected in 9(25.7%) and 16(45.7%) out of 35 their hands, respectively. Twelve out of sixteen $B.$ $cereus$ isolates(70.0%) produced enterotoxin. The results indicate that the hand hygiene of nursery school children needs to be improved. Comparing before and after hand washing in educated and non-educated group, the reduction effect of total aerobic bacteria on their hands was 0.42 and 0.60 log CFU/hand, respectively. The educated group showed 0.18 log CFU/hand higher reduction effect than non-educated group but microorganism did not eliminate perfectly. From the results, using a hand sanitizer after washing with soap and the continuous hand washing education are required to control the contaminated bacteria on nursery school children's hands.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.959-965
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• 2016

In 1994, a new cultivar 'Joyskin' was created from a cross between the cultivars 'Whangkeumbae' and 'Waseaka' at the Pear Research Institute of the National Institute of Horticultural and Herbal Science, Rural Development Administration. In 2006, the 'Joyskin' was selected from among the 317 seedlings resulting from the cross for its skin and taste qualities. Regional adaptation tests were conducted in nine regions and in ten experimental plots from 2006 to 2011. The cultivar was named in 2011. 'Joyskin' showed a vigorous growth habit and semi-spread characteristics similar to 'Whangkeumbae'. The average full bloom date for 'Joyskin' was April 21st, which was also similar to 'Whangkeumbae'. The optimum fruit ripening time was September 6-8th, which was six or eight days earlier than 'Whangkeumbae'. The fruit was round in shape and the skin was a golden yellow color at maturity. The average fruit weight was 320 g and the flesh firmness was $2.5kg/8mm{\varphi}$. The firmness of the fruit skin determined by a blade-type plunger of texture analyzer was 22.9 N, which was significantly different from that of 'Whangkeumbae' 29.9N. Stone cell analysis of 'Joyskin' by phloroglucinol-HCl, showed that 'Joyskin' stone cells were small in size and few in numbers cpmpared to those of cultivars of was 'Manpungbae', 'Niitaka', and 'Whangkeumbae'. The patent application for 'Joyskin' was submitted in April, 2012 (Grant No. 2012-337). In 2016, 'Joyskin' (Grant No. 5895) was registered as a separate record, with uniformity and stability per Korean Seed Industry Law.

• Journal of Life Science
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• v.14 no.4
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• pp.650-656
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• 2004

Oryza grandiglumis (CCDD, 2n=48), one of the wild rice species, has been known to possess fungal-,bacterial-, and insect-resistance against sheath blight, rice blast, bacterial leaf blight and brown plant hopper (Nilaparvata lugens). To rapidly isolate differentially expressed genes responding to fungal and wounding stress, wounding and yeast extract were treated to O. grandiglumis for 24 hrs. Suppression subtractive hybridization (SSH) method was used to obtain differentially expressed genes from yeast extract and wounding treated plants. Seven hundreds and seventy six clones were obtained by subcloning PCR product, and colony array and screening were carried out using radio-isotope labeled cDNA probes prepared from the wounding and yeast extract treated plants. One hundred and fifteen colonies were confirmed as true positive ones. Average insert size of the clones were ranged from 400 bp to 700 bp and all the inserts were sequenced. To decide the identity of those clones, sequences were analyzed by sequence homology via GenBank database. The homology search result showed that 68 clones were matched to the genes with known function; 16 were related to primary metabolism, 5 to plant retrotransposons, 5 to defense related metallothionein-like genes. In addition to that, others were matched to various genes with known function in amino acid synthesis and processing, membrane transport, and signal transduction, so on. In northern blot analysis, induced expressions of ogwfi-161, ogwfi-646, ogwfi-663, and ogwfi-695 by wounding and yeast extract treatments were confirmed. The result indicates that SSH method is very efficient for rapid screening of differentially expressed genes.