• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.550-556
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• 2000

Three floating islands were constructed on the surface of the reservoir, each consisting of 10 16-㎡ (4${\times}$4 m) segments, made of wood frames and floats. Three species of aquatic macrophytes were planted in each island on June, 1998. Phragmites australis was considered as the suitable aquatic macrophyte for the floating islands since it maintained the most efficient root and shoot balance among the macrophytes. The net primary productivity of P. Australis was 3,604 g/㎡ based on dry weight in 1999, with uptake rates of nitrogen and phosphorus estimated at 77.4 g/㎡/yr and 5.7 g/㎡/yr, respectively. The result of water quality simulation for the floating islands showed that, through adsorption of nutrients and light screening, they could reduce the amount of phytoplankton, thereby decreasing COD concentration.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.27-33
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• 2014

Hydrolysates of Trianthema portulacastrum in acidified methanol were evaluated for their total phenolic (TP) constituents and respective antioxidant activities using in vitro assays (i.e., 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, percent inhibition of linoleic acid peroxidation, and ferric reducing power). The observed results indicate that root, shoot, and leaf fractions of T. portulacastrum contain 50.75~98.09 mg gallic acid equivalents/g dry weight of TP. In addition, these fractions have substantial reducing potentials (0.10~0.59), abilities to inhibit peroxidation (43.26~89.98%), and DPPH radical scavenging capabilities ($6.98{\sim}311.61{\mu}g/mL$ $IC_{50}$). The experimental data not only reveal T. portulacastrum as potential source of valuable antioxidants, but also indicate that acidified methanol may be an ideal choice for the enhanced recovery of phenolic compounds with retained biological potential for the food and pharmaceutical industry.

• Asian Journal of Turfgrass Science
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• v.4 no.1
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• pp.24-30
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• 1990

This study was carried out to search for growth and quality -of turfgrass by Nitrogen source (Urea Ammonium sulphate) and organic matter, and to obtain methods of pr6per turfgrass management by the results. This experiment was conducted in turf field from 1988 to 1989. The results of this experiment was summarized as follows; 1.Without application of organic matter, turfgrass growth between urea and ammonium sulphate was not significant, however ammonium sulphate resulted in superior to urea in total dry weight when organic matter was applied. 2.The addition of organic matter showed significant effect on color rating and visible quality, and ammonium sulphate was higher quality than urea. 3.Shoot density increased, particularly in ammonium sulphate treatment, when organic matter was applied. 4.Rhizome and stolon were shown significant effect in urea treatment by the application of organic matter. 5.Surface soil pH was allowed to become slightly acid by the ammonium sulphate treatments, but soil acidity remained mostly unaffected when organic matter was supplied. 6.Total nitrogen of log tissue and organic matter content increased when organic matter w-as applied.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.292-298
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• 1997

To compare the growth pattern of ginseng plant under between conventional shading(light transmittance rate 3％) and polyethylene net shading(light transmittance rate 10％), the distribution of leaf area, specific leaf weight (S. L. W), leaf and stem dry weight and changes in light intensity were investigated in 2, 4 and 6 year old ginseng plant populations. Light transmittance rate(L.T.R.) was 3％ at front line, 2％ at middle line and 1.5％ at rear line under conventional shading but it was 12, 10 and 8％ under polyethylene net(P.E) shading, respectively. In 2 year old population, there was a little difference in the growth characteristics investigated between conventional and P.E. shading. In 4 year old field, the leaf area, stem and leaf dry weight decreased in large amount in the order of middle, and rear line on ridge under conventional shading, but with a little difference under P.E. shading. And these trends enlarged in 6 year old field with appearance of a large part of shoot over furrow from ridge planted ginseng. Root yield index was much lowered at the rear 3rd, 4th and 5th line of the conventional shading bed, but there was no yield difference among lines except 5th lines under the P.E. shading with higher yield by 28％ than conventional shading.

• Korean Journal of Weed Science
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• v.2 no.2
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• pp.141-145
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• 1982

In order to determine the possibility of reducing rice injury caused by CNP and butachlor application, the effects of IAA seed presoaking on CNP and butachlor action against early growth of rice seedlings were investigated under flooded direct-seeding and dry-seeded conditions. CNP and butachlor injury to rice was reduced by soaking rice seeds at 0.1, 1.0 and 10ppm of IAA solution for 36 hours before seeding under flooded condition and thus shoot length and dry weight of rice seedlings increased compared with those of IAA untreated seedlings. IAA seed pretreatment also overcame the inhibitory effect of CNP and butachlor under dry-seeded condition. Effect on reducing rice injury by IAA pretreatment was more remarkable when CNP applied under dry seeded condition and butachlor under flooded condition.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.62-70
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• 1994

This study was conducted to find out if there are some differences in germination, growth and morphological characteristics between rice(Oryza saliva) and barnyardgrass(Echinochloa crus-galli) under various cropping patterns and to abtain the fundamental information on weed control method in direct seeded rice. Rice was broadcast on soil-surface(Broadcast rice), drill seeded in soil(Drilled rice) and barnyardgrass was drill seeded in soil(Barnyardgrass) under dry(Dry condition) and water direct seeded condition(Water condition). Also rice was transplanted with 8-day seedlings(8 -day-old seedling) and 25-day seedlings(25-*day-old seedling) under transplanting condition(Transplanting condition) At 1, 2, 3, 5, 7, 10, 15 and 20 days after seeding or transplanting(DAS/T), plants were harvested to examine their germination, growth and morphology. The major results were as follows ; Until 5 DAS/T growth of rice and barnyardgrass were well established under dry condition but under water condition growth of shoots was mainly elongated. At 20 DAS/T barnyardgrass had greater plant height and shoot fresh weight than rice under direct seeded condition, while plant height and shoot fresh weight of rice was greater than those of barnyardgrass under transplanting condition. Root length of barnyardgrass was greater under the dry, drilled, direct seeded conditions than that of rice under the water, broadcast, transplanting condition, respectively. And root fresh weight of rice under direct seeded condition was similar to that of barnyardgrass but that of rice under transplanting condition was significantly greater than that of barnyardgrass. Barnyardgrass only formed mesocotyls and its length increased with increased depth of seeding. Leaf stage and leaf area of barnyardgrass was greater under the dry, drilled than those of rice under water, broadcast conditions, respectively, while those of rice was greater than those of barnyardgrass under transplanting condition. Chlorophyll contents were higher in barnyardgrass, dry direct seeded rice, transplanted rice, water direct seeded rice in descending order.

• Korean Journal of Medicinal Crop Science
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• v.7 no.4
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• pp.296-302
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• 1999

This experiment was conducted to study the effect of $CO_2$(0, 2, 500, 5, 000, 10, 000ppm) enrichment by enabling ventilation on micropropagation of multi-shoot and on the saponin contents in vitro in Korean ginseng (Panax ginseng C. A. Meyer). Embryo was cultured in Murashige and Skoog medium added 3mg/ l of Indolbutyric acid, Benzyladenin and Gibberellic acid $(GA_3)$, respectively. $CO_2$, enrichment had little effects on the number of adventitious buds and shoots originated from adventitious buds. The ratio of differentiated shoots to adventitious buds were about 50% in $CO_2$, enrichment treatment. The shoots originated from adventitious bud showed more rapid growth and had larger leaf area than the shoots originated from the leaf primordia did. The number of shoot primordia was the highest in 2, 500ppm of $CO_2$ enrichment treatment. On the contrary, 10,000ppm of $CO_2$, enrichment made smaller the number of shoot primordia and ratio of shoots to shoot primordia. The range of shoots differentiated was from shoot primordia were 15. 4 to 23. 9. The rate of dry weight of cultured shoots showed lowest (7. 5%) in control and highest (8. 59%) in 2, 500ppm of $CO_2$, enrichment. Rate of in vitro flower in control was 7.6% and that in 2500ppm of $CO_2$ was about twice (15.7-16.3%) as much as in control. Flower number per a embryo cultured was about 1.2-1.3. In the multi-shoots with callus enriched by 2, 500ppm of $CO_2$, the contents of crude saponin and ginsenosides in multi-shoots alone were higher than in multi-shoots with callus. The characteristics of ginsenosides in multi-shoots were especially the higher content of ginsenoside Rd, Re, and $Rg_1$.

• Korean Journal of Medicinal Crop Science
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• v.18 no.1
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• pp.51-55
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• 2010

This study was conducted to investigate the effect of planting position on the growth characteristics, yield and ginsenoside content in Panax ginseng C.A. Meyer at different growth stages. Referring to shoot growth characteristics, stem length, stem diameter and leave area were higher at front than rear, increasing as the proceeding of growth stages. But a lower chlorophyll contents was caused at front compared to rear and decreased as the proceeding of growth stages contrarily. According to root characteristics, root length and main body length were higher at front, with a positive correlation to growth stages, which was also shown on fresh root weight and dry root weight with the maximum in August. Meanwhile, the effect of planting position on ginsenoside content could also be definite by the highest content at front showing high light intensity, increasing as the proceeding of growth stages as well.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.37-44
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• 1988

A serial study on differential response in absorption and translocation of $^{14}C$-oxyfluorfen was conducted by use of a group of selected rice cultivars as the tolerant or the susceptible to oxyfluorfen. Trial 1. Differential response in absorption and translocation of selected cultivar group. The susceptible cultivar group has reached as higher rate as 209%, 193%, 344%, 204% and 152% of the tolerant cultivar group in root absorption rate per unit dry weight, lower-shoot absorption rate, higher shoot absorption rate, whole amount of absorption, and the rate of translocation from bottom to shoot, respectively. Trial 2. Differential Response in Absorbtion and translocation of selected cultivar as affected by exposed portion and time. ${\bullet}$ Regardless of cultivar, the rate of root absorption has effectively realized but the translocation was significantly limited. ${\bullet}$ Lower portion of shoot has also achieved a higher amount of absorption but the translocation was very limited. ${\bullet}$ By relaying the exposure time. the amount of root absorption was ted increasing, and persistent absorption was rather effective in the susceptible (cv. Mushakdanti) cultivar than the tolerant (cv. Chokoto). ${\bullet}$ Translocation of oxyfluorfen from shoot to root was tended to easily attaining in both cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.303-308
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• 2001

To investigate the partitioning of newly absorbed N derived from NO$_3$- and NH$_4$$^{+}$, 6 mM $K^{15}$ NO$_3$ or 3 mM ($^{15}$ NH$_4$)$_2$ was fed continuously in Italian ryegrass (Lolium multiflrum L.) for 7 days. Nitrogen metabolites (nitrate, amino acid, soluble- and insoluble protein) were analyzed at the end of $^{15}$ N feeding. Dry weight in shoot, stubble and root was not significantly different between NO$_3$$^{[-10]}$ and NH$_4$$^{+}$ feeding. Total nitrogen content in all three organs was significantly higher in NH$_4$$^{+}$ than NO$_3$$^{[-10]}$ feeding. Sum on N content in reduced N fractions (amino acids + proteins) in shoot, stubble and roots in NH$_4$$^{+}$ feeding increased by 13.3, 12.5 and 35.4 %, respectively, compared to NO$_3$$^{[-10]}$ feeding. The Relative Specific Activity (RSA, percentage of newly absorbed $^{15}$ N relative to total N in a sample) values of amino acids and insoluble proteins were significantly higher in NH$_4$$^{+}$ feeding. Total amount of newly absorbed $^{15}$ N in NO$_3$$^{[-10]}$ and NO$_3$$^{[-10]}$ feeding was 52.3 and 69.5 mg/plant on dry matter basis, respectively. In both NH$_4$$^{+}$ and NO$_3$$^{[-10]}$ grown plants, most of the N was allocated to the shoot, 67.5% in NH$_4$$^{+}$ feeding and 58.8% NO$_3$$^{[-10]}$ feeding, respectively. The $^{15}$ N amount incorporated in the reduced N compounds (amino acids and proteins) in NH$_4$$^{+}$ grown plants significantly increased by 74.8% compared to NO$_3$$^{[-10]}$ grown plants. The increase of the $^{15}$ N amount assimilated to amino acids in NH$_4$$^{+}$ grown plants was remarkably higher in roots as more than 7.25 times compared to NO$_3$$^{[-10]}$ feeding. These results indicated that Italian ryegrass was much efficiently utilized NH$_4$$^{+}$-N for the synthesis of reduced N compounds.reduced N compounds.