• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.135-145
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• 2009

This research was conducted to investigate the effect of various phosphorus concentrations in fertilizer solution on growth of and nutrient uptake by 'Chugyang' egg plant (Solanum melongena L.). Tissue and soil analyses were also conducted to set the threshold levels of phosphorus in plants when disorders develop for phosphorus deficiency or excess. Brown and purple areas developed on the margin of mature leaves and it enlarged rapidly in P deficient plants. The fruits in P deficient plants were small and dull purple in color. When P were excess in fertigation solution, the margins of lower leaves became scorched and it enlarged to inner part of the leaves. The fruits of P excess plants became small and had the curl shape. The tissue $PO_4$-P contents in the most recently fully expanded leaves and dry weight of full above ground plant tissue at 35 days after transplanting showed quadratic response ($y=0.7887+0.2394x-0.0197x^2$) and cubic response ($y=10.43+14.47x-4.7642x^2+0.3977x^3$) to elevated $PO_4$-P concentrations, respectively. When 10% reduction in dry weight set to threshold levels, optimum tissue $PO_4$-P contents are between 0.98 to 1.35%. The yield determined at 150 days after transplanting also showed cubic response to elevated phosphorus concentrations in fertigation solution ($y=1194.6+1502.2x-454.5x^2+35.64x^3$). When the 10% reduction in yield is set to threshold levels, the tissue $PO_4$-P contents for maximum yield should be around 1.53% to 2.25% in most recently fully expanded leaves at 150 days after transplanting.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.303-308
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• 2015

The consumption of leaf vegetables has been steadily increasing in Korea. Leaf vegetables are used for "Ssam (vegetable wrap-up), eaf vegetables has been steadily increasing in Korea. Leaf vegetables are used for asoned condiments inside several layers of young vegetable leaves. This study investigated the effect of air temperature on the growth and phytochemical contents of beet (Beta vulgaris L.) and Ssamchoo (Brassica lee L. ssp. namai) grown in a closed-type plant factory system where fluorescent lamps were used as an artificial light source. Seeds of beet and Ssamchoo were sown in a peat-lite germination mix. The roots of 20-day-old seedlings were washed, and the seedlings were planted on a styrofoam board and grown in hydroponic beds for 25 days under fluorescent light. Plants were exposed to one of three different air temperature regimes (20, 25 and $30^{\circ}C$ during the day combined with $18^{\circ}C$ during the night), which were monitored with a sensor at 30 cm above the plant canopy. Increased plant height and leaf area were observed in beet at $25^{\circ}C$ and $30^{\circ}C$ compared to $20^{\circ}C$. For Ssamchoo, the greatest plant height, leaf area, fresh weight and dry weight were obtained at $20^{\circ}C$. Ascorbic acid content of beet and Ssamchoo leaves were highest at $30^{\circ}C$. In beet, total polyphenol and flavonoid contents were higher at $20^{\circ}C$ (42.4, $197.0mg{\cdot}g^{-1}DW$) and $25^{\circ}C$ (46.9, $217.0mg{\cdot}g^{-1}DW$) than $30^{\circ}C$ (22.4, $88.0mg{\cdot}g^{-1}DW$). In Ssamchoo, total polyphenol and flavonoid contents were also higher at $20^{\circ}C$ (79.2, $268.2mg{\cdot}g^{-1}DW$) and $25^{\circ}C$ (66.3, $258.3mg{\cdot}g^{-1}DW$), respectively, than $30^{\circ}C$ (53.7, $134.7mg{\cdot}g^{-1}DW$). Hence, the optimum temperature appears to be $20^{\circ}C$ for growing both beet and Ssamchoo in a closed-type plant factory system with fluorescent light.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.103-110
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• 2018

This study was conducted to investigate the optimum irrigation method for propagation of cutting strawberry ($Fragaria{\times}ananassa$ Duch. cv. Maehyang) plantlet in summer season. The cutting strawberry plantlets were planted in 24-cell tray ($60{\times}34{\times}10cm$) filled with commercial mixed medium (Tosilee) and placed in semi closed-type small plastic tunnel. Each semi closed-type small plastic tunnel was treated as follows; control (non-treatment), over head irrigation (twice a day), capillary mats irrigation (twice a day), or fog irrigation (30 minutes turn on and 10 minutes off from 8:00 to 18:00). The strawberry plantlets were rooted during 8 days in the semi closed-type small plastic tunnel, and then plastic film was removed. Growth parameters, such as plant height, root length, number of primary roots, petiole length, leaf length, leaf width, crown diameter, SPAD, leaf area, fresh and dry weights of the shoot and root, were measured at 61 days after cutting. Relative humidity in tunnel was high in the order by fog irrigation, over head irrigation, capillary mats, and the control as 72.5, 56.3, 45.8, and 29% on average, respectively. However, the air temperature was similar in all treatments. On the 4 and 8 days, the rooting rate of strawberry plantlet was significantly higher in the over head irrigation and fog irrigation treatments. Plant height, petiole length, crown diameter, and leaf area were highest in the over head irrigation and fog irrigation treatments. In addition, fresh and dry weights of shoot were greater in over head irrigation and fog irrigation treatments than the others. Dry weight of root was differed significantly heaviest in the fog irrigation treatment. However, root length, no. of primary roots, SPAD value, and fresh weight of root were not significantly different in all treatments. These results indicated that growth and rooting for propagation of cutting strawberry plantlet 'Maehyang' were best achievement in the over head irrigation and fog irrigation treatments.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.829-838
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• 2015

Garlic (Allium sativum L.), one of the oldest cultivated crops, is the most widely used Allium species belonging to the family Lilliaceae. In this study, growth characteristics, photosystem II activity, and antioxidative enzyme activity were investigated in five temperatures ($10-30^{\circ}C$) during early growth stage of garlic to determine the optimum temperature for cultivation and assess the effects of high temperature on early growth of garlic. Vegetative growth (e.g., shoot height, number of leaves) of garlic plants was greater in the temperature ranges of $15-25^{\circ}C$. However, dry weight (of shoot, bulb, and total plant) of garlic was significantly greater at $20^{\circ}C$, compared to either below or above $20^{\circ}C$. $F_v/F_o$ and $F_v/F_m$ values were highest at $15-20^{\circ}C$, and decreased above $25^{\circ}C$. The chlorophyll a fluorescence induction OKJIP transient was also considerably affected by high temperature; the fluorescence yields $F_i$ and $F_P$ decreased considerably above $25^{\circ}C$, with the increase of $F_k$ and $W_k$. Activities of catalase and superoxide dismutase in leaves and peroxidase in roots were high in $20-25^{\circ}C$, and decreased significantly in $30^{\circ}C$. These results indicate that a growth temperature of $30^{\circ}C$ inhibits early growth of garlic and that it is desirable to culture garlic plants near $20^{\circ}C$. Fluorescence parameters such a $F_v/F_o$, $F_v/F_m$, $F_k$, $ET_o/CS_m$, and $PI_{abs}$ were significantly correlated with dry weight of whole garlic plants (p < 0.01), indicating that these fluorescence parameters can be used for early assessment of high temperature effects even though the damage to the plant is not very severe.

• Korean Journal of Poultry Science
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• v.36 no.1
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• pp.57-67
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• 2009

These studies were conducted to investigate the various dietary CP and ME feeding effect on productivity, blood composition and meat quality in cross bred chicks. Seven hundred twenty one day old cross bred chicks (Hanhyup Samho) were alloted to the floor pen for early starting (0~2 weeks), starting (3~5 weeks), growing (6~8 weeks), finishing period (9~10 weeks). Dietary ME and CP were 3,000, 3,100 kcal/kg, and 22% for early starting period, 19, 20, 21% for starting period, 18, 19, 20% for growing period, 17, 18, 19% for finishing period. Weight gain and feed consumption were weekly measured and feed conversion ratios were calculated. Blood and breast meat were collected at the end of experiment. Birds fed ME 3,100 kcal/kg diets improved significantly compared with others for the first two weeks (P<0.05). Feed conversion was statistically improved in CP (22)21% treatment relative to that of CP (22)20% from three to five weeks of age. No difference were found from 6 to 8 weeks of age. Weight gain and feed conversion also improved in ME 3,100 kcal/kg treatments, but feed intake decreased significantly in CP ($22{\times}21{\times}20$)19% treatment for the rest of experimental period (P<0.05). There was interaction between ME and CP for the first five weeks (P<0.05). Blood total protein showed higher in ME 3,100 kcal/kcal treatment than ME 3,000 kcal/kg (P<0.05). There were no differences in albumin, total cholesterol and glucose, but CP ($22{\times}20{\times}19$)18 treatment showed higher glucose than other treatments (P<0.05). Cooking loss, tenderness and water holding capacity were not different. However, pH was dependent on dietary ME, CP and existing the interaction between ME and CP treatments (P<0.05). As the results of this experiment, ME and CP were confirmed the 3,000 kcal/kg, 22% for the first two weeks 3,100 kcal/kg, 21% from three to five weeks of age, 3,100 kcal/kg, 18% for the growing period, 3,100 kcal/kg, 17% for the rest of period. However, further research would be required to confirm more optimum dietary nutrition for cross bred chicks.

• The Korean Journal of Ecology
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• v.26 no.5
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• pp.273-280
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• 2003

Saline conditions invoke oxidative stress attributed to the overproduction of reactive oxygen species (ROS). Changes in quantum efficiency and antioxidative enzyme activity upon salt treatment were examined in a salt-tolerant plant, Atriplex gmelini, to test the hypothesis that salt tolerance of A. gmelini is due to the increased activity of antioxidative enzymes. A. gmelini showed optimum growth at 100 mM NaCl producing 116% of the shoot dry weight over control plants in 0 mM NaCl treatment. Healthy growth persisted up to 300 mM NaCl treatment maintaining normal internal water content and dry weight. No photochemical stress or damages on antioxidative defense system was obvious in plants of 2 and 4 day salt treatment which was indicated by increased quantum efficiency (Fv/Fm value), decreased stress index (Fo/Fm value), and increased activity of antioxidative enzymes such as SOD, APX, GR. However, the plants treated with 400 mM NaCl showed decrease in growth and in antioxidative enzyme activity although the enzyme activity was still higher than that of the 0 mM NaCl treated plants (l31%, 114%, and 134% of the SOD, APX, and GR activity, respectively). Interestingly, another important antioridative enzyme that scavenges H₂O₂ in plant cells, CAT, showed rapid decrease in its activity as salt concentration increased; 38%, 22%, 15% of the 0 mM NaCl treated plants at 200, 300, 400 mM NaCl treatments, respectively. It appears that the enzymes in ascorbate-glutathione cycle such as APX and GR play the major roles in scavenging ROS produced by salt stress in A. gmelini. After 6 days of salt treatment, the damage in photochemical and antioxidative defense system was indicated by decreased Fv/Fm value and increased Fo/Fm value. A. gmelini appears to cope with short term salt treatment by enhanced activity of the antioxidative defense system, whereas long term stress invoke oxidative stress by increased ROS due to the damages in photochemical and antioxidative system.

• Korean Journal of Poultry Science
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• v.35 no.4
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• pp.367-373
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• 2009

This experiment was conducted to determine optimum dietary levels of dietary energy and protein for laying performance and egg quality in organic laying hens. In a $2{\times}3$ factorial arrangement, 360 Hy-Line pullets (21 wk of age) were randomly assigned to experimental diets with 2,800, 3,080, and 3,360 kcal of ME/kg of diet, each containing 16 and 18% CP, respectively. Each dietary treatment was replicated 4 times, and feed and water were provided ad libitum. Experimental birds were raised in floor and received 14h of light throughout 52 weeks of experimental period. The birds were observed for feed consumption, egg production, egg weight, egg mass, feed conversion ratio, Haugh unit, shell thickness, and shell color at 30, 50, and 70 wk of age. Egg production, egg weight, and egg mass were higher (P<0.05) in hens receiving diets with 2,800 kcal/kg of ME/kg of feed than those fed diets containing 3,080 and 3,360 kcal of ME/kg of diets. Eggshell breaking strengths were not significantly different among the dietary ME and CP concentrations. Eggshell thickness was higher (P<0.05) in hens receiving diets with 3,360 kcal of ME/kg of feed than those fed diets containing 2,800 and 3,080 kcal of ME/kg of diets at 50 and 70 week. With increasing in dietary energy levels, the concentrations of blood total cholesterol were also significantly increased. Overall, the laying hens fed organic diet of 2,800 kcal ME/kg and 16% CP showed superior egg production than those of other dietary regimens.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.137-142
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• 2011

$TiO_2$-coated bamboo activated carbon has been prepared and utilized under UV irradiation as a pretreatment method for an effective biodegradation of the recalcitrant polyaromatic hydrocarbons (PAHs). The anatase $TiO_2$ was successfully coated on the bamboo activated carbon (AC) and it showed the highest photoactivity against methylene blue. In the absence of the PAHs-degrading bacteria PAHs having low molecular weight (i.e., naphthalene, acenaphthylene, acenaphthene, and fluorene) were degraded by 9.8, 76.2, 74.1, and 40.5%, respectively. Higher molecular weight PAHs, however, maintained high residual concentrations of PAHs (400-1,000 ${\mu}g$/L) after the same treatment. On the other hand, the overall concentrations of PAHs became lower than 340 ${\mu}g$/L when the pretreated PAHs were subjected to biodegradation by a PAH-degrading consortium for a week. Herein, phenanthrene, anthracene, fluoranthene, and pyrene were removed by 29.3, 61.4, 27.0, and 44.3%, respectively, indicating the facilitated potential biodegradation of PAHs. Activated carbon coated with $TiO_2$ appeared to inhibit growth of PAH degraders on the surface of AC, indicating planktonic degraders were dominantly involved in the PAH biodegradation in presence of the $TiO_2$-coated bamboo AC. It was proposed that an effective remediation technology for the recalcitrant PAHs could be developed when an optimum pretreatment process is further established.

• Korean Journal of Poultry Science
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• v.44 no.4
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• pp.275-282
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• 2017

This study was conducted to investigate the effect of dietary silicate based complex mineral (SCM) on the performance of broiler chicks. Four hundred fifty one day old Cobb ${\times}$ Cobb broiler chicks were fed with commercial diets at 0%, 0.05%, 0.10%, 0.15% and 0.20% SCM with five replicates for five weeks. Weight gain, feed intake and feed conversion were measured weekly, and blood composition, immunity and meat quality were evaluated at the end of experiment. During overall period weight gain in chicks fed diet containing 0.1% SCM was significantly increased as compared with that of control (p<0.05). Feed intake showed no consistency among the treatments. Feed conversion appeared to increase in the chickens fed with SCM addition diets during prestarter period. Albumin, glucose and other blood parameters related to chicken health tended to improve at the level of 0.05% SCM addition treatments. Drip loss in breast meat was significantly decreased in more than 0.05% SCM addition (p<0.05). The expression of IL-2 (Interleukin-2) in blood increased significantly in the chickens fed with SCM of 0.05% or 0.10% level than other treatments (p<0.05). The optimum SCM concentration for commercial dietary supplementation for improving broiler performance and other health-related parameters was 0.10%.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.2
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• pp.125-130
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• 2005

This study was conducted from March 16 to July 6 in 2004 at Jeju Island to investigate the influences of sowing dates(on March 16, March 26, April 5, April 15 and April 25) on creeping bentgrass vegetation. The result obtained were summarized as follows; Plant height was 22.7 cm at March 16 planting. It was longest but after that planting, plant height gradually shorted. Then it was shortest at April 25 planting(16.6 cm). Root length and Minolta SPAD-502 chlorophyll reading value were directly proportional plant height response. Leave and root weight were greatest at March 16 planting. It were 1,373 kg /10a and 2,374 kg /10a, respectively. These weight decreased gradually as planting was delayed from March 16 to April 25. Degree land cover and density of creeping bentgrass were $98.0\%$ and $99.3\%$, respectively, at March 16. After that planting they were decreased ($97.5\%$, $98.7\%$). But degree land cover and density of weed tended to increased gradually as the planting was delayed. The number of weed species were increased from March 16 to April 25. It showed increase that Poa annua, Stellaria media and Chenopodium album var. centrorubrum(at March 16 planting), Poa annua, Digitaria adscendens and Chenopodium album var. centrorubrum(at March 26 planting), Digitaria adscendens, Chenepodium album var. centrorubrum and Stellaria media(at April 5 planting), Digitaria adscendens, Stellaria media and Chenopodium album var. centrorubrum(at April 15 planting), Digitaria adscendens, Polygonum hydropiper, Chenopodium album var. centrorubrum(at April 25 planting). Based on the these findings, optimum sowing date for growth of creeping bentgrass seems to be about early seeding in atmospheric phenomena and volcanic ash soils of Jeju island.