• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.422-428
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• 2001

Retention relative times(RRTs) of PAH molecules and their derivatives in gas chromatography are trained and predicted in testing sets using a multiple linear regression(MLR) and an artificial neural network(ANN). The main descriptors of PAHs and their derivatives in QSRR are the square root of molecular weight(sqmw), molecular connectivity($^1{\chi}_v$), molecular dipole moment(D) and length-to-breadth ratios(L/B). The results of MLR shows that a heavy molecule has a propensity for long retention time. L/B closely related with slot model is a good descriptor in MLR. On the other hand, ANN which is not effected by the linear dependencies among the descriptors were exclusively based on molecular weight and molecular dipole moment. The variances which shows the accuracy of prediction for retention times in testing sets are 1.860, 0.206 for MLR and ANN, respectively. It was shown that ANN can exceed the MLR in prediction accuracy.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.21-29
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• 2017

This study was conducted to determine the effects of artificial lighting sources on vegetative growth of Phalaenopsis and Doritaenopsis (an intergeneric hybrid of Doritis and Phalaenopsis) orchids. One - month - old plants were cultivated under fluorescent lamps, cool - white light - emitting diodes (LEDs), or warm - white LEDs at 80 and $160{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. The blue (400 - 500 nm) : green (500 - 600 nm) : red (600 - 700 nm) : far - red (700 - 800 nm) ratios of the fluorescent lamps, cool-white LEDs, and warm-white LEDs were 1 : 1.3 : 0.8 : 0.1, 1 : 1.3 : 0.6 : 0.1, and 1 : 2.7 : 2.3 : 0.4, respectively. Each light treatment was maintained for 16 weeks in a closed plant-production system maintained at $28^{\circ}C$ with a 12 h photoperiod. The longest leaf span, as well as the leaf length and width of the uppermost mature leaf, were observed in plants treated with warm-white LEDs. Plants grown under fluorescent lamps had longer and wider leaves with a greater leaf span than plants grown under cool-white LEDs, while the maximum quantum efficiency of photosystem II was higher under cool-white LEDs. The vegetative responses affected by different lighting sources were similar at both 80 and $160{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Leaf span and root biomass were increased by the higher light intensity in both cultivars, while the relative chlorophyll content was decreased. These results indicate that relatively high intensity light can promote vegetative growth of young Phalaenopsis plants, and that warm - white LEDs, which contain a high red-light ratio, are a better lighting source for the growth of these plants than the cool-white LEDs or fluorescent lamps. These results could therefore be useful in the selection of artificial lighting to maximize vegetative growth of Phalaenopsis plants in a closed plant - production system.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.37-41
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• 2011

This experiment was carried out to find an optimum shading level for the growth of root and shoot, and to find the effect of shading level after August on the induction and growth of inflorescence of Phalaenopsis hybrid. The shading levels were 50%, 60%, 70%, 80% and 90% of natural light($1200{\mu}molm^{-2}s^{-1})$. The $CO_2$ uptake, transpiration rate, carbohydrate content, fresh weight and dry weight of Phalaenopsis hybrid were higher at 50-60% level than the others. But, it was diminished when the shading level was increased from 70% to 90%. Inflorescence length, the number of inflorescence and flower per plant all increased under 50-60% shading level and the day needed for the flowering after treatment decreased. Especially, the induction of inflorescence was depressed and flowering is not occurred under 90% during experiment period. These results suggest that the optimal shading level for the growth of Phalaenopsis including inflorescence was founded to be 50-60% in the season of light intensity and amount of sunshine decrease after august.

• The Plant Pathology Journal
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• v.37 no.2
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• pp.173-181
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• 2021

The genus Streptomyces demonstrates enormous promise in promoting plant growth and protecting plants against various pathogens. Single and consortium treatments of two selected Streptomyces strains (Streptomyces shenzhenensis TKSC3 and Streptomyces sp. SS8) were evaluated for their growth-promoting potential on rice, and biocontrol efficiency through induced systemic resistance (ISR) mediation against Xanthomonas oryzae pv. oryzicola (Xoc), the causal agent of rice bacterial leaf streak (BLS) disease. Seed bacterization by Streptomyces strains improved seed germination and vigor, relative to the untreated seed. Under greenhouse conditions, seed bacterization with consortium treatment TKSC3 + SS8 increased seed germination, root length, and dry weight by 20%, 23%, and 33%, respectively. Single and consortium Streptomyces treatments also successfully suppressed Xoc infection. The result was consistent with defense-related enzyme quantification wherein single and consortium Streptomyces treatments increased peroxidase (POX), polyphenol oxidase, phenylalanine ammonia-lyase, and β,1-3 glucanase (GLU) accumulation compared to untreated plant. Within all Streptomyces treatments, consortium treatment TKSC3 + SS8 showed the highest disease suppression efficiency (81.02%) and the lowest area under the disease progress curve value (95.79), making it the best to control BLS disease. Consortium treatment TKSC3 + SS8 induced the highest POX and GLU enzyme activities at 114.32 µmol/min/mg protein and 260.32 abs/min/mg protein, respectively, with both enzymes responsible for plant cell wall reinforcement and resistant interaction. Our results revealed that in addition to promoting plant growth, these Streptomyces strains also mediated ISR in rice plants, thereby, ensuring protection from BLS disease.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.85-85
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• 2020

South Korea experiences few large scale erosion and sedimentation problems, however, there are numerous local sedimentation problems. A reliable and consistent approach to modelling and management for sediment processes are desirable in the country. In this study, field measurements of sediment concentration from 34 alluvial river basins in South Korea were used with the Modified Einstein Procedure (MEP) to determine the total sediment load at the sampling locations. And then the Flow Duration-Sediment Rating Curve (FD-SRC) method was used to estimate the specific degradation for all gauging stations. The specific degradation of most rivers were found to be typically 50-300 tons/㎢·yr. A model tree data mining technique was applied to develop a model for the specific degradation based on various watershed characteristics of each watershed from GIS analysis. The meaningful parameters are: 1) elevation at the middle relative area of the hypsometric curve [m], 2) percentage of wetland and water [%], 3) percentage of urbanized area [%], and 4) Main stream length [km]. The Root Mean Square Error (RMSE) of existing models is in excess of 1,250 tons/㎢·yr and the RMSE of the proposed model with 6 additional validations decreased to 65 tons/㎢·yr. Erosion loss maps from the Revised Universal Soil Loss Equation (RUSLE), satellite images, and aerial photographs were used to delineate the geospatial features affecting erosion and sedimentation. The results of the geospatial analysis clearly shows that the high risk erosion area (hill slopes and construction sites at urbanized area) and sedimentation features (wetlands and agricultural reservoirs). The result of physiographical analysis also indicates that the watershed morphometric characteristic well explain the sediment transport. Sustainable management with the data mining methodologies and geospatial analysis could be helpful to solve various erosion and sedimentation problems under different conditions.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.227-232
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• 2015

This experiment was carried out to investigate the effects of shading materials (aluminum specific-shading screen and polypropylene non-woven fabric) and shading ratio (50% and 70%) on climatic changes, cut-flower quality, and yield of spray rose cultivars for export during high temperature periods. The daily cumulative solar radiations were higher with the aluminum specific-shading screen, especially with 50% shading compared to polypropylene non-woven fabric. Air temperature and root zone temperature within rockwool media greatly decreased with the aluminum specific-shading screen, but relative air humidity was not different among shading methods. Chlorophyll contents (SPAD values) were slightly higher with aluminum-specific shading screen than with polypropylene non-woven fabric, and were higher with 50% than with 70% aluminum specific-shading screen. Except for 'Lovely Lydia', marketable and exportable yields of all cultivars were higher with 50% than with 70% aluminum shading treatment. In addition, flowers talk length, stem diameter, number of node and 7ea-leaflet, and floret number tended to be better with aluminum specific-shading screen. Flower stalk length was higher with 70% than with 50% aluminum shading treatment. Chromaticity of petals slightly increased, and vase life was 0.5-2.5 days longer for each cultivar with aluminum specific-shading screen than with polypropylene non-woven fabric.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.202-208
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• 2020

The objective of this study was to select the right species among Agastache in the family Lamiaceae as the result of growth analysis and functional substance analysis. Among 22 species of Agastache, five species (Agastache cana, Agastache foeniculum, Agastache rugosa 'Spike Blue', Agastache rugosa 'Spike Snow', Agastache rupestris) were selected by referring to United States Department of Agriculture (USDA)'s plant hardiness zone area and Korea's one based on USDAs. These plants were cultured at 24 ± 1℃ and 18 ± 1℃ (day and night temperatures, respectively) and 65 ~ 75% relative humidity in a hydroponic culture system for 4 weeks. In terms of growth analysis experiment, stem length, root length, leaf width, leaf area, leaf number, SPAD value, and fresh and dry weights of shoots and roots were measured. The results showed that A. rugosa SS and A. rugosa SB have a higher overall balance value than other species. When compared functional substance value (rosmarinic acid, tilianin, and acacetin) of five species, A. rugosa SS and A. rugosa SB are significantly higher than other species in Agastache. It seems to be directly proportional to the growth analysis results. When considering the growth and functional substance part comprehensively, A. rugosa SS and A. rugosa SB are the most optimal high-value species among Agastache.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.148-156
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• 2016

This study examined effects of Enterobacter ludwigii SJR3 showing a high 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, on growth of tomato plant and its expression of stress-related genes under drought and salt stress. SJR3 strain was inoculated at $10^6cell/g$ soil to 4-week grown tomato plants, and drought and salt stresses were treated. After additional incubation for 1 week, root length, stem length, fresh weight and dry weight of tomato plants treated with SJR3 increased by 37.8, 37.2, 96.8 and 146.6%, respectively compared to those of uninoculated plants in drought stress environment, and they increased by 19.2, 25.4, 19.5, and 105.8%, respectively in salt stress environment. Proline content in tomato leaves increased significantly under stress conditions as one of a protecting substance against stresses, but proline contents in tomato treated with SJR3 decreased by 62.1 and 54.1%, respectively. Relative expression of genes encoding ACC oxidase, ACO1 and ACO4, ethylene response factor genes ERF1 and ERF4, and some other stress-related genes were examined from tomato leaves. Compared to the non-stressed tomato, expressions of all stress-related genes increased significantly in the stressed tomato, but gene expressions in the inoculated tomato were similar to those of no-stressed control tomato. Therefore, E. ludwigii SJR3 may play an important role in mitigating drought and salt stress in plants, and can increase productivity of crops under various abiotic stresses.

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.131-144
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• 1995

To determine the structure of chromosome and to identify the sex chromosome of Ginkgo biloba and G. biloba var. fastigiata, the samples were obtained from root tips of trees growing in seven different provinences. The results are as follows. The basic number of somatic chromosomes was 2n=24. The range of a relative length of long chromosome was between $14.88{\sim}11.18{\mu}m$ and that of short chromosome was $8.11{\sim}6.24{\mu}m$. The chromosome sets were composed with one long pairs of m type and 11 short pairs of sm or st type. These short pairs showed the continuous descending in length. There was a satellite on the short arm of the Longest chromosome pair, and were satellites of the one or both long arm of 7th or 8th chromosome pair which were sm or st type, or the shortest st type chromosome pair. Sometimes, a satellite on the short arm of the longest chromosome pairs of Ginkgo biloba was double satellite, but that of G. biloba var. fastigiata was not. Karyotype was $2n=24=2^{2s}A^m+2B^{st\;or\;sm}+2C^{st}+2D^{st}+2E^{st}+2F^{st\;or\;sm}+2G^{sm}+2^{2s}H^{sm}\;or\;(^{1s}H^{sm}+H^{sm})+2I^{st}+2J^{st}+2K^{st}+2^{2s}L^{st}\;or\;(^{1s}L^{st}+L^{st})$. The male and female trees were not apparently distinguished by the chromsome structures. However the differences between the satellites could be used to identify the male and females. The male tree has double satellite on short arm of a longest chromosome pairs and females' has not. Also female trees have a satellite on a short chromosome more frequently than male trees.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.233-238
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• 2005

Growth of Campanula punctata 'Rubriflora' plantlets, as affected by three levels of photosynthetic photon flux (PPF), 70, 110, and $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, two levels of $CO_2$ concentration, 500 and $1,500{\mu}mol{\cdot}m^{-1}$, and two levels of number of air exchanges per hour (NAEH), 0.1 and $2.8 h^{-l}$, was studied. Explants were obtained from photomixotrophically-micropropagated plantlets. Four explants were planted in each $3.7{\times}10^{-4}m^3$ polycarbonate box containing MS basal medium and no added sucrose. Explants were cultured under cool-white fluorescent lamps for $16h{\cdot}d^{-1},\;at\;25\pm1^{\circ}C$ temperature, and $70\~80\%$ relative humidity In treatments of $2.8h^{-1}$ NAEH, a 10mm round hole made on the vessel cap was sealed with a microporous filter. For higher $CO_2$ concentrations in the culture room, $CO_2$ gas was provided from a tank of liquefied $CO_2$. Fresh and dry weights, length of the longest root, and number of leaves significantly increased with increasing PPF and especially $CO_2$ concentration. Length of the longest root, number of leaves, fresh and dry weights, and chlorophyll concentration were enhanced with increased NAEH. However, leaf area was the smallest in the $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}\;PPF\;2.8h^{-1}$ NAEH and especially, $1,500{\mu}mol{\cdot}mol^{-1}\;CO_2$ concentration treatment. Treatment effect became more produced with time. Overall, treatment with $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}\;PPF\;and\;1,500{\mu}mol{\cdot}mol^{-1}\;CO_2$ gave the most vigorous growth.