• Korean Journal of Weed Science
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• v.16 no.1
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• pp.14-20
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• 1996

Growth, nutrient uptake and photosynthesis as affected by submersion of shoot in pickerel weed (Monochoria vaginalis Presl.) were determined. The shoots of pickerel weeds in hydroponic culture were subjected to the submerged or emerged condition at 3- or 5-leaf stage for 8 or 10 days. Under submerged condition, growth in plant height was enhanced, but leaf number, leaf area, fresh and dry weight were reduced compared to those under the emerged condition. Similar responses in growth to submergence were obtained with the pickerel weeds rooted in the soil. Under submergence, chlorophyll content increased during the first 2 days, but thereafter remarkably decreased at 3-leaf stage and after the first 4 days at 5-leaf stage. Compared to the emerged condition, uptakes of $NH_4\;^+$-N, $NO_3\;^-$-N, $P_2O_5$ and $K^+$ were reduced, but uptakes of $Ca^{++}$ and $Mg^{++}$ increased under the submerged condition. Photosynthetic rate of shoot under water, measured by $CO_2$electrode, showed the maximum by 210 ${\mu}$moles $HCO_3\;^-$/g F.W. at the 8th day after submergence(DAS) at 3-leaf stage and 320 ${\mu}$moles $HCO_3\;^-$/g F. W. at 6 DAS at 5-leaf stage. These results indicate that pickerel weeds grow much better when the shoot is air-exposed and are less tolerable to submergence at 3 leaf-stage than at 5-leaf stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.333-338
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• 2008

The tea has traditionally been used as a foodstuff by unique flavor, however recently not only the diversity of consumer demands but also the public interest in unique favorite and functional aspects have increased. It has been also reported that the main components contained in the leaves of tea (Camellia sinensis) include total nitrogen, free amino acids, polyphenols, and fiber, of which catechin has powerful bioactive effect such as anti-cancer, anti-aging, and anti-diabetic. (-)-Epigallocatechin gallate (EGCG) which is a major phenolic constituent of green tea extract has received considerable attention for a variety of important bioactivities. This study was carried out to obtain useful information for tea breeding programs, and to investigate the concentration of quality and functional related components in Korean indigenous tea germplasms. Korean indigenous tea lines were classified into three groups of sprout time, i.e, early, medium and late sprout time, and the ratio were 20%, 43% and 37%, respectively. There was a difference in characteristics among these Korean indigenous tea lines, leaf width of those ranged from 19.8 to 75 mm, leaf length was 35.5-160.0 mm, and leaf area was $660-8,400\;mm^2$. Experimental data on chlorophyll content (SPAD value) of Korean indigenous tea genetic resources ranged from 51.3 to 82.3. The concentrations of the total nitrogen, total free amino acids, and theanine were ranged 4.18-6.07%, 2.87-4.58%, and 1.64-2.66%, respectively. Also, catechin concentration showed from 11.54 to 15.07%, and concentration of caffeine was 2.82-4.23%. These results indicated indicated that it is possible to select elite lines with high concentration of quality related components and low concentration of caffeine from Korean domestic tea germplasms.

• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.216-227
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• 2008

To understand eutrophication in the upper regions of brackish Lake Sihwa with a limited water exchange, temporal and spatial distributions of pollutants in water and sediment were investigated from March to October in 2005 and 2006. Also, pollution levels of water and sediment were estimated by trophic state index (TSI) and sediment quality guideline (SQG). Total nitrogen (TN), total phosphorus (TP), organic matter (COD), and chlorophyll $\alpha$ (Chl-$\alpha$) concentrations in the surface waters were largely varied temporally and spatially, and the variations were highest in the middle areas where strong halocline was formed. Chl-$\alpha$ concentrations in the middle area were very high in April (>$900\;{\mu}g\;L^{-1}$) when algal blooms (red tides) occurred. The relationships between TN and Chl-$\alpha$ (r=0.31), and TP and Chl-$\alpha$ (r=0.65) indicated that the algal growth was primarily affected by phosphorus rather than nitrogen. The distribution of COD was similar to that of Chl-$\alpha$, indicating that the autochthonous organic matters may be a more important carbon source, especially in the middle areas. The brackish water regions were classified as eutrophic or hypertrophic based on their TSI values ($69{\sim}76$). In addition, the content of nutrients (especially TP) in surface sediments were classified as severe polluted state, except the upper areas. Major causes of the eutrophication observed were probably due to high nutrients loading from watersheds, the phosphorus release from anaerobic sediment, and long retention time by the limited water exchange through the sluice gates.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.2
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• pp.145-152
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• 2002

To compare the Carbon metabolic response to high temperature stress in Zoysiagrass [Zoysia matrella (L.) Merr.] and Creeping bentgrass (Agrostis palustris Huds) with respect to heat tolerance, C metabolites were determined from April to September. Sampling was carried out on an established golf course (Muan Country Club, Chonnam, Korea). Shoot mass(g Dry weight per hole cup) of creeping bentgrass started to decrease from June and recovered from August whereas that of zoysiagrass was less varied. Chlorophyll content in creeping bentgrass was significantly higher than zoysiagrass until July, and then decreased by 43% from July to August. Zoysiagrass contained higher soluble sugar than creeping bentgrass throughout experimental period. Soluble sugar in zoysiagrass increased about 58% from April to May, and less varied until August. Soluble sugar in creeping bentgrass slightly increased until July and sharply decreased at August. Starch concentration in zoysiagrass continuously decreased to September after a significant increase from April to May. A remarkable fluctuation in both starch and fluctuation concentration was observed between June and August showing high accumulation for June to July and high degradation for July to August. These results suggest that through creeping bentgrass suffers much severely from high temperature stress than zoysiagrass especially June to August. An active accumulation and degradation in nonstructural carbohydrate in creeping bentgrass during this period might be associated with heat stress.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.284-288
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• 2005

This study was conducted to clarify the effects of supplying methods of selenium on the growth and Se uptake of hydroponically grown tomato plants. Tomato seeds (Lycopersicum esculentum Mill. cv. Momotaro T-93, Daki Seed Co.) were sown in plug tray with fifty holes, and raised for sixty days. Tomato seedlings transplanted to coco fiber slabs were supplied with the nutrient solutions adjusted to EC $2.3dS{\cdot}m^{-1}$ and pH $5.8\~6.2$ recommended by the Japanese Horticultural Experiment Station. Selenium forms used were inorganic $SeO_2$ (here in after referred to Se) and organic selenium chlenium with sugar fatty acid ester (here in after referred to chelated-Se). 10 ppm selenium solutions were treated to tomato plants with foliar applications, drenching, and foliar application plus drenching. Growth characteristics in terms of plant height, number of leaves, leaf area and chlorophyll content were significantly increased in the plot of foliar application ot Se, and in the plot of foliar application plus drenching of chelated-Se than other plots, respectively. Transported contents of selenium into the tomato fruits were highest as 0.302 ppm in the plot of foliar application plus drenching of chelated-Se. Also, it had tended to be higher in the plot of foliar application plus drenching than in the plots of foliar application or drenching in both of Se and chelated-Se. Foliar application and drenching of organic chelated-Se were effective to produce the functional tomato fruits.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.181-187
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• 2002

The overall objective of this study was to improve tomato fruit quality, while maximizing yield. The variety of 'Momotaro' was grown in the basic nutrient solution of 1.6 dS.m$^{[-10]}$ which was supplemented by three levels of seawater with EC 1.0, 2.0 or 3.0 dS.m$^{[-10]}$ . Tomato plants were cultivated in cool seasons. Plant growth characteristics were compared between treatments, and fruits were classified to analyse fruit quality characteristics according to ripening stages： MG, Br, Br＋3, Br＋5, Br＋7 and Br＋10. Adding seawater generally did not affect the shoot growth parameters such as plant height, leaf length, leaf width, internode length and chlorophyll content. Adding seawater negatively affected yield parameters such as the height and weight of fruit, marketable fruit weight per plant and marketable fruit yield. Therefore, the more yield reduction was obtained with the increasing level of seawater treatment. Fruit quality was improved by seawater treatment. The degree of the effect for $^{\circ}$Bx degree and sugars were the highest with the EC of seawater 2.0~3.0 dS.m$^{[-10]}$ , and at the Br＋5~Br＋7 of ripening stages. The relative abundance of tomato flavor, volatile components, was not generally affected by the seawater treatment with an exception of 6-methyl-5-hepten-2-one. The relative abundance of most volatile components increased as ripening progressed. The increment began at the Br stage and showed the highest increment at the Br＋5~Br＋7 stages. The results from these experiments suggest that seawater treatment of EC 3.6 dS.m$^{[-10]}$ for hydroponics is good for improving tomato quality. Fruit quality is the best at the Br＋5~Br＋7 ripening stages. It is considered that these results may be applied far use in hydroponic culture to improve fruit quality with minimum yield reduction.

• Korean Journal of Environmental Agriculture
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• v.28 no.2
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• pp.179-185
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• 2009

This study was carried out to investigate the effect of selenium treatment on the growth of vegetables sprout. Four vegetables, such as cabbage, lettuce, pak-choi and leaf mustard were examined under various selenium treatments (0, 1, 5, 10, 25, 50, 100 mg $L^{-1}$). Seed germinations in cabbage, pak-choi and leaf mustard were significantly inhibited at high concentration of selenium treatment. However, seed germination in lettuce was not much inhibited. Growth characteristics, such as soot length, root length, fresh weight and chlorophyll contents, were not much decreased at 1 mg $L^{-1}$ of selenium and then significantly inhibited with the increase of selenium concentration at above 5 mg $L^{-1}$ in all four vegetables. The selenium content increased linearly with the increase of selenium concentration. At the range of 1 to 25 mg $L^{-1}$ of selenium treatment, selenium contents in vegetables were 0.11 to 1.15 of cabbage, 0.16 to 0.61 of lettuce, 0.13 to 1.31 of pak-choi and 0.14 to 1.13 mg $g^{-1}$dw of leaf mustard, respectively. These results showed that treatment of selenium with the range of 1 to 5 mg $L^{-1}$ could be used to produce the selenium enriched vegetable sprouts.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.498-507
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• 2006

The main objective of present study was to evaluate how seasonal rainfall influenced natural habitat conditions of 10 metric habitat variables along with ionic conditions and suspended solids in the Woopo Wetland during August 2002-July 2003. Largest spatial variabilities in total suspended solids (TSS) occurred during the summer monsoon and the inorganic suspended solids (ISS), expressed as a inorganic proportion of total solids, showed linearly increasing trend from the upstream to downstream. This phenomenon was mainly attributed to counter flow of turbid water from the main Nakdong-River. During the flooding, ISS : TSS ratio showed large increases (92%) in the downstream than the upstream (43%). For this reason, transparency declined (mean=0.13 m, range=0.08-0.21 m) largely in the downstream reach and thus, chlorophyll-a concentration showed low values (range: $4.2-8.6\;{\mu}g\;L^{-1}$), indicating a direct influence on primary productivity or algal growth by inorganic turbidity. In the 2nd survey, ISS averaged 4.0 mg $L^{-1}$ (3.3-4.8 mg $L^{-1}$), thus the ISS decreased by 14 fold, compared to the ISS in the 1st survey during the flooding, while organic suspended solids (OSS) values were greater than those of ISS, indicating a dominance of organic solids. This condition was similar to solid contents in the 3rd survey, but showed a large difference compared to the 4th survey during the growing season. Habitat health assessments, based on 10 metric habitat variables, showed that QHEI values were greatest in the growing season (May) than any other seasons and largest spatial variations occurred in the 2nd survey. Overall, dataset suggest that seasonal episodic flooding during the monsoon may largely contribute nutrient cycling and sediment contents in the Woopo Wetland and Topyung Stream.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.185-196
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• 2008

This Study was conducted to evaluate the effect of liquid fertilizer containing medium of on growth of shoot and root in creeping bentgrass (Agrostis palustris Huds. cv. Pennlixs). According to application method of liquid fertilizer, the experiment plot was designed as follows; NF : non-fertilizer; CF : compound fertilizer(21-17-17) only; T500, T300, T100 : compound fertilizer +liquid fertilizer solution diluted 500, 300, 100 folds, respective; L500 : only liquid fertilizer solution which contained the medium of Lactobacillus confusa and Pichia anomala diluted 500 folds. The every treatments was arranged by a completely randomized complete block designs with three replications. The order of turf qualities like leaf color index and chlorophyll content in treatments showed T500 T300 T100 $\geq$ CF > NF. In treatment applied with compound fertilizer, the dry weight of shoot increased by about 13% in T500, T300 and T100 than CF, and that of root about 25% in just T300. Dry weight of shoot and root increased by 88% and 44% in L500 than NF, respectively. As compared with CF, T/R ratio in T500, T300 and T100 increased by 20%, 11% and 21%, respectively and root length 7%, 8% and 3%. In comparison with NF, T/R ratio and root length in L500 increased by 39% and 74%. These results suggested that the application of liquid fertilizer containing medium of Lactobacillus confusa and Pichia anomala induced the development of turf quality and growth by promoting root growth in creeping bentgrass.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.537-545
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• 1995

Quality changes of lettuce were studied during storage to investigate the efficiency, cooling properties and the washing and storage effects of immersion-type hydrocooling. As a result of plotting the nondimensionalized lettuce temperature versus cooling time, its cooling rate coefficient was shown to be $-0.365\;min^{-1}{\sim}-0.255\;min^{-1}\;(R^2=0.99{\sim}0.88)$. Rate of weight loss was not significantly (p>0.05) different between lettuces with various treatment conditions during storage at $5^{\circ}C$. However, during storage at $15^{\circ}C$, weight loss of hydrocooled lettuce was lower than that of non-treated lettuce after from 10 to 15 days. Especially, The lettuce packed with PE was more effective than that packed with try in terms of packing condition after hydrocooling. Lettuce pretreated with sterilizing agent, packed with PE vinyl film, removed residual water after hydrocooling had lower decaying rate than any other lettuces. Changes of L and b values in hydrocooled lettuce were slower than those of non-treated one. During changes of chlorophyll content, the initial value, $115.7{\sim}147.3\;mg%$ was decreased to $50{\sim}60%$ after 25 days of storage at $5^{\circ}C$ and within 15 days of storage at $15^{\circ}C$. It could be presumed that the addition of sterilizing agent reduced the initial level of overall total and coliform count and its growth rate during storage. The respiration rate of hydrocooled lettuce at $5^{\circ}C$ was $23.95\;mg{\cdot}CO_2/kg\;hr$, which is 10% of those of non-treated lettuce.