• Korean Journal of Weed Science
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• v.30 no.3
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• pp.215-224
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• 2010

A greenhouse experiment was conducted to determine the effects of medium components and shade treatment on the growth, contents of total phenolics and flavonoids, and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity of Youngia sonchifolia. Substrates combined with coco peat and perlite (ratio 70:30 or 50:50, v/v) showed higher plant length, leaf area, and fresh weight than single substrate (P<0.05). Shade treatment also significantly reduced plant height, root length, leaf areas, and fresh weight (P<0.05) with increasing of the degree. Shading treatment, however, increased contents of total phenolics [mg ferulic acid equivalents $kg^{-1}$ dry wt.] and total flavonoids [mg naringin equivalents $kg^{-1}$ dry wt.] in shoot parts of Y. sonchifoli, showing 110.2 to 119.2 and 128.3 to 146.7 mg $kg^{-1}$, respectively. The antioxidant potential of the methanol extracts from the plants dose-dependently increased DPPH free radical scavenging activity, and the activity was higher in shoots (50.2 to 80.8%) than in roots (47.7 to 49.8%), and in shading treatment than in no shade.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.205-216
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• 2002

This study was conducted to examine the effect of long-day (LD) period before short-day (SD) treatment on the vegetative growth of greenhouse-grown cut chrysanthemum cv. Reagan Improved at Wageningen Agricultural University, The Netherlands. Rooted cuttings of cut chrysanthemum cv, Reagan Improved were transplanted on 6th, 13th, 20th of September and all of them were treated with LD before SD treatment on 27th of September, The periods from transplanting until final harvest were 70, 77, and 84 days for 1, 2, and 3 week-LD treatment, respectively. The final plant height increased in the plot of 3 week-LD period and decreased in the plot of 1 week-LD period before the SD treatment. Total fresh weight and the leaf area were increased more in the plot of 3 week-LD period than that of 1 week-LD period, but the absolute growth rate after SD treatment was the same on plant growth rate and increase of the number of leaves in all treatments. The final dry matter production (g.m$^{-2}$ ) was increased more in the plot of 3 week-LD period than that of 1, 2week-LD period before SD treatment. Plant height and fresh weight were followed by the condition of LD period. In addition, dry mass production was highest in 3 week-LD period.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.139-146
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• 2004

Kenaf (Hibiscus cannabinus L.), an annual plant of the family Malvaceae, is considered to be the most promising for alternative plants with potential use as a non-wood fiber source. The objectives of this study were to select the optimum seeding date and adaptable cultivar among newly introduced kenaf cultivars (Everglades-41, Tainung-2 and Chingpi-3) in Jeju island, and to clarify the photosynthetic characteristics of those cultivars. Among the three cultivars, the fresh shoot weight per unit area of Chingpi-3 at harvest season showed highest through all seeding dates, that of while Everglades-41 was the lowest. The difference of shoot yield at harvest mainly due to seedling stand rate and plant number per unit area among the cultivars. The Chingpi-3 showed the highest shoot fresh weight in the seeding date of May 11 and decreased trend in the late seeding dates. Net photosynthesis rate was higher on Everglades-41 with entire type leaf than other two cultivars with palmate type leaf. The activity of ribulose-1,5-bisphosphate carboxylase/foxygenase (rubisco) estimated from the A-Ci curve showed highest in Chingpi-3 among three cultivars. These results suggest that Chingpi-3 might be adaptable cultivar with seeding date of around May 10 for kenaf production in Jeiu island.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.1-6
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• 1999

The author studied the soil microarthropoda's fauna, vertical distribution, seasonal fluctuation, and the relationship between the number of soil microarthropoda and environmental factor(pH) in survey area. 3949 soil microarthropoda were collected in survey area. They included Arachnida(48.6%), Collembola(23.5%), Hymenoptera(l9.9%), and Isoptera, etc. Fresh length was the longest(1l3.6 mm) in broad-leaf forest on Mt. Chilgap which is non-industrial complex area, and the shortest(46.8 mm) in pine forest at Yochon industrial complex. The population density of soil microarthropoda was the highest in summer and the lowest in winter. The number of soil microarthropoda was higher in Mt. Keryong and Chilgap, non-industrial complex area, than Yochon and Daesan, industrial complex area. The number of soil microarthropoda increased from spring to summer and decreased from autumn to winter. Vertically, soil microarthropoda were more abundant in the second layer subsoil(0∼5 cm) in spring, in the first layer(5∼10 cm) in summer and autumn, and in the third layer(0∼15 cm) in winter. Diversity index was higher in non-industrial area(1.02) than industrial complex area(0.73). Biodiversity index was the highest in the second soil layer, in pine forest on Mt. Keryong(l.60) and the lowest in the third soil layer, in broad leaf-forest, at Daesan industrial complex(0.24).

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.424-430
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• 2018

This study was carried out to estimate growth characteristics of hot pepper and to develop predicted models for the production yield based on the growth parameters and climatic elements. Sigmoid regressions for the prediction of growth parameters in terms of fresh and dry weight, plant height, and leaf area were designed with growing degree days (GDD). The biomass and leaf expansion of hot pepper plants were rapidly increased when 1,000 and 941 GDD. The relative growth rate (RGR) of hot pepper based on dry weight was formulated by Gaussian's equation RGR $(dry\;weight)=0.0562+0.0004{\times}DAT-0.00000557{\times}DAT^2$ and the yields of fresh and dry hot pepper at the 112 days after transplanting were estimated 1,387 and 291 kg/10a, respectively. Results indicated that the growth and yield of hot pepper were predicted by potential growth model under plastic tunnel cultivation. Thus, those models need to calibration and validation to estimate the efficacy of prediction yield in hot pepper using supplement a predicting model, which was based on the parameters and climatic elements.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.652-665
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• 1997

Allelopathic effects on some crops(rice, barley, wheat, Chinese cabbage, leaf mustard, onion, welsh onion, tobacco, red pepper) for extracts of Phytolacca americana and Armoracia rusticana were investigated in MS solid medium. Germination percentage, radicle length, hypocotyl length, plant height, fresh weight, dry weight, and seedling vigor were rapidly inhibited by methanol extract from Phytolacca americana according to increase of the concentration in test plants. Autotoxicity of Phytolacca americana began to appear at concentrations greater than 50$\mu$l methanol extracts per 20ml medium. The fresh weight and dry weight of Phytolacca americana were also decreased by its own methanol extract according to increase of the concentration. Initial amounts of growth of all crops were also inhibited by methanol extracts from Armoracia rusticana, but the inhibitory effects were lowered than those of methanol extracts of Phytolacca americana. Of four fractions, ethyl acetate, petroleum ether, $1^{st}H_2O, 2^{nd}H_2O$, reextracted from methanol extracts of Phytolacca americana, the ethyl acetate fraction showed the highest allelopathic effects on germination percentage and initial amounts of growth. Chlorophyll contents of rice, barley and Chinese cabbage were more inhibited in the ethyl acetate fraction than in the other fractions. Free proline content of Chinese cabbage was increased 31.2 times in the 100$\mu l$ ethyl acetate fraction, and the contents of rice and barley were also increased according to concentration levels in the ethyl acetate fraction.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.68-75
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• 2017

Demand for dwarf mondo grass (DMG; Ophiopogon japonicus 'Nanus') as an ornamental garden plant is expected to grow in the future. The purpose of this study was to investigate the levels of shade tolerance and ground cover by growing DMG under a variety of shade conditions for 18 months (May 2015~October 2016). DMG plants grown in bare ground for 3 years in Jangheung-gun, Jeonnam were used for testing. In an experimental site created in Naju city in Jeonnam, the DMG was planted in planters ($70cm{\times}70cm{\times}24cm$) and covered with a shading curtain to block natural light. Shaded conditions were then arranged under different levels of shade (0%, 55% and 75%). When the plants were grown, growth (leaf size, the number of leaves, fresh weight and dry weight) and ground coverage of DMG were analyzed. According to the results, DMG growth in terms of leaf size and the number of leaves was statistically higher under zero shade (full sunlight), when compared to other shaded conditions. DMG's fresh and dry weights were significantly greater under 0% and 55% shade, compared to those under 75% shade. The degrees of shade tolerance required for normal growth of DMG were found in the range of 0~50%, meaning that more than 50% shade may decrease plant growth. There were no statistical differences in ground coverage rates of DMG under different levels of shade. When 220 tillers were planted per $1m^2$ of plot, up to 80% of the area was covered by DMG after 18 months. Since DMG requires nutrient-rich soil to grow, sufficient nitrogen fertilizers are proposed to accelerate the ground cover of DMG. As DMG remained alive over the winter in the experiments, this study also suggests that DMG can be planted in the southern temperate region.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.23-27
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• 1988

This experiment was conducted to determine germination ability, life cycle, regrowth ability of Portulaca oleracea L. The newly harvested seeds from P. oleracea flowered before July 15 were able to germinate, but percent germination decreased markedly as the flowering time was later than July 15, showing no germination of seed collected at Sept. 12 which were flowered at August 30, 76.5% of seeds can be germinated in the light as seed stored in room condition for 90 days, but in dark condition, it needed 2 years of seed storage for germination. Low temperature treatment at $2^{\circ}C$ for 5 days enhanced seed germination of P. oleracea in both light and dark conditions. The maximum vagetative growth was observed at 30 to 75 days after seeding. The late seeding time such as July 1 shortened the period of vegetative growth. However, regardless of the seeding times, the first flowering was observed at about 40 days after seeding. Leaf numbers, shoot lengths, fresh and dry weights were greatly affected by the seeding dates, showing that the earlier seedings produced significantly higher shoot length, fresh and dry weight, leaf numbers and branch numbers than those of the late seedings. When all branches were removed on 68 days after seeding, their regrowth ability was 50.3% and cuttaged branches showed 78.1% regrowth as compared to intact plant.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.4
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• pp.265-270
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• 2003

This study was conducted to determine the influence of seeding date on growth, characteristic yield and chemical composition of Italian millet (Setaria italica) from April 20 to May 30, 2003(April 20, May 1, May 20 and May 30) in Jeju. A local variety was seeded on days to heading were lessened as seeding date was delayed. The plant height was longest when seeded on 1 May(131cm) than at the other seeding dates. Stem diameter, number of leaves, leaf length and leaf width had the similar trend with plant height. SPDA reading values were greater at earlier seedings. Fresh forage yield was greatest (43.28MT/ha) at 1 May seeding and decreased gradually before or after this seeding date. Dry matter yield, crude protein yield and total digestible nutrient (TDN) yield had nearly the same tendency with fresh forage yield. Crude protein, crude fat, NFE and TDN contents were greatest at 30 May seeding and then decreased earlier seedings. Crude ash and crude fiber content tended to decreased as seeding was delayed. Based on the these findings, optimum seeding date for forage production of Italian millet seems to be early May in Jeju island.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.67-75
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• 1996

Capsicum annuum 'Nokkwang' plug seedlings were treated with 9 different day and night temperatures to investigate on growth and differentiation in controlled environment conditions. The plant height was the most affected by day temperature and DIF and stem length was the similler results as plant height. However, Leaf unfolding rate and leaf length and width increased as average daily temperature increased. and especially fresh weight was worst at ADT was $15^{\circ}C$ and increased as ADT increased. In contrast with fresh weight, chlorophyll content calculated highest when ADT was $15^{\circ}C$, and decreased as NT increased respectively. The stem lengths were not significantly different among treatments with exception of DT/NT=15/$15^{\circ}C$ which significantly decreased. The ultimate +DIF condition, DT/NT=30/$15^{\circ}C$, caused high T/R ratio due to abundant top growth. It is concluded that DT is $22.5^{\circ}C$, and NT is ranged from $15^{\circ}C$ to $22.5^{\circ}C$ to be produced short, healthy plug seedlings in Capsicum annuum 'Nokkwang'.