• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.2
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• pp.85-89
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• 2018

The effects of distribution temperature due to season all changes on quality and storability of baby leaf beet (Beta vulgaris L.) was examined in modified atmosphere (MA) packages. The beet leaf had been harvested at the 10 cm leaf length stage and packaged with an oxygen transmission rate (OTR) film of $1,300cc{\cdot}m^{-2}{\cdot}day^{-1}{\cdot}atm^{-1}$ and then held at 4 different distribution temperatures which were $-2^{\circ}C$, $4^{\circ}C$, $20^{\circ}C$, or $30^{\circ}C$ for 5 hrs and then stored for 18 days at $8^{\circ}C$. The loss of fresh weight of packged baby leaf beet was lowest at the $4^{\circ}C$ treatment, and below 0.6% in all distribution temperature treatments. The atmosphere composition in packages did not show any significant differences among treatments. The oxygen conc. was the highest at 18.0% after the $4^{\circ}C$ treatment, carbon dioxide conc. showed the maximum value of 4% at the $30^{\circ}C$ and $-2^{\circ}C$ treatments, and ethylene conc. was highest at the $10^{\circ}C$ treatment after 10 days in storage. The hardness was the highest at the $4^{\circ}C$ treatment on the final storage day. The $4^{\circ}C$ treatment showed the highest visual quality and the lowest off-odor and aerobic plate count. Therefore, it is necessary to establish a low-temperature distribution system which is controlled under $4^{\circ}C$, because the baby leaf beet's storability and microbial growth are effected even during a short time of 5 hrs during the distribution process.

• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.43-48
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• 2001

Chlorophyll fluorescence of needles of Korean fir (Abies koreana) plants and environmental factors of their natural habitat were investigated in order to obtain the information for environmental adaptation and conservation of Korean fir plants. The photochemical efficiency of photosystem II, Fv/Fm, of Korean fir needles was significantly low (0.19-0.36) in the winter, whereas it was high (0.8-0.86) in the summer. The Fv/Fm value of the winter was slightly higher at mid-day than at dawn, suggesting that mid-day environmental conditions of the winter were favorable on needles of Korean fir plants. In contrast, the mid-day Fv/Fm value of the summer maintained high (around 0.8). It indicates that mid-day environmental conditions of the summer did not induce photodamage, although it caused a slight decrease in the Fv/Fm values. The non-photochemical fluorescence quenching (NPQ) of Korean fir needles was very low (0-0.01) all through the day in the winter. However, it was high (0.76) at mid-day in the summer. These results suggest that Korean fir plants have a system for the protection of PS II from mid-day environmental stresses of the summer. In the winter, the Fv/Fm values were positively correlated with temperature, light intensity and relative humidity, although NPQ values showed no correlation with any of them. In the summer, the Fv/Fm values were positively correlated with relative humidity but negatively correlated with temperature and light intensity. These results indicate that increase of tempera-ture, light intensity and relative humidity lead to promotion of the photochemical efficiency in the winter and high temperature and light intensity may cause photoinhibition in the summer.

• Journal of Aquaculture
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• v.1 no.2
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• pp.121-133
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• 1988

Strongylocentrotus pulcherrimus is one of the very important fishery stock in this country since its high demand for raw gonad. Although the demand has been continuously increasing, the natural stock of this species seems to be decreasing. Since fresh macroalgae are not always available, the substitution of terrestrial vegetables for algae as a principal food was examined for the intensive indoor culture of the sea urchin. The results from the studies on selective and non-selective feeding habits and nutritional efficiencies using 13 food stuffs (6 macroalgae, 5 vegetables and 2 animal products) indicate that algae can be substituted with vegetables in sea urchin culture. Although the growth of body weight was the highest when sea urchins were fed Undaria Pinnatifida, the gonad index of the sea urchins fed on spinach, radish leaf and lettuce was higher than that of this brown alga. Considering the different food efficiencies of body and gonad growth, spinach and radish leaf will be adequate during gonad growth season, while lettuce and Chinese cabbage will be suitable for test growth season. In particular, radish leaf, which is usually not eaten by humans, could be highly beneficial and very economical in the sea urchin culture.

• Journal of Life Science
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• v.28 no.8
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• pp.917-922
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• 2018

Centella asiatica is one of the local herbs that is claimed to possess various physiological effects. C. asiatica also accumulates large amounts of pentacyclic triterpenoid saponins known as centelloids. These terpenoids usually include asiatic acid, asiaticoside, madecassoside, and madecassic acids. In the present study, to understand the changes of triterpene glycoside levels in the different shoot tissues of C. asiatica during seasonal cultivation, we investigated the High-Performance Liquid Chromatography (HPLC) analysis via different extraction methods, such as water, 20% ethanol and methanol extracts. Significant increases were observed in the levels of madecassoside and asiaticoside in the leaf extracts by methanol compare with extracts using water or 20% ethanol. Additionally, we also analyzed the various antioxidant activity in the different shoot tissues of C. asiatica using different extracts, such as leaves, petioles and both materials. Among these petiole extracts showed high 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTs) scavenging activity in all extracts, whereas 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity exhibited high activity levels in the leaf part using methanol and ethanol extracts. Levels of total phenolics and flavonoid also showed the highest levels in the leaf tissues using all extracts such as methanol, ethanol and water. Our results indicated that the increased levels of triterpene glycoside and antioxidant activity in the leaf parts of the C. asiatica were indicating that useful metabolites were mainly maintained through seasonal cultivation such as madecassoside, asiaticoside.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.95-106
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• 2010

The performance of Community Land Model version 3.5 - Dynamic Global Vegetation Model (CLM-DGVM) was evaluated through a comparison with the observation over temperate deciduous forest in Gwangneung, Korea. Influence of plant phenology, composition of plant functional type, and climate variability on carbon exchanges was also examined through sensitivity test. To get equilibrium carbon storage, the model was run for 400 years driven by the observed atmospheric data at the deciduous forest of the year 2006. We run the model for 2006 with the equilibrium carbon storage at Gwangneung forest and compared the model output with the observation. A comparison of leaf area index (LAI) between the model and observation indicated that the simulated phenology poorly represented the timing of budburst, leaf-fall, and evolution of LAI. Senescence of the phenology was delayed about four weeks and the simulated maximum LAI (of 5.8 $m^2$ $m^{-2}$) was greater than the observed value (of 4.5 $m^2$ $m^{-2}$). The overestimated LAI contributed to overestimation of both gross primary productivity (GPP) and ecosystem respiration $(R_e)$ through increased photosynthesis and foliar autotropic respiration $(R_a)$, respectively. Despite the discrepancy between the simulated and observed LAI, the simulated tree carbon storage amounts were comparable with the reported values at the site. Change in plant phenology from the simulated to the observed reduced more than six weeks of the plant growth period, resulting in the decreased amount of GPP and $R_e$. These values, however, were still higher (~10% of GPP and 40% of $R_e$) than the observed values. The effect of change in plant functional type composition (from dominant temperate deciduous forest to the coexistence of temperate deciduous and needle leaf forests) on the estimated amount of GPP and $R_e$ was marginal. The influence of climate variability on carbon storage amounts was not significant. The simulated inter-annual variation of GPP and $R_e$ from 1994 to 2003 depended on annual mean air temperature and total radiation but not on precipitation. Other deficiencies of CLM3.5-DGVM have been discussed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.2
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• pp.141-147
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• 2005

This study investigated air pollutant levels and physiological variation of Ginkgo biloba in Chuncheon. The results were as follows: The annual average concentrations of $SO_2,\;NO_2\;and\;PM10$ were 0.004ppm, 0.013 ppm and $66{\mu}g/m^3$, respectively. The volume weighted average concentrations of ionic components were $SO_4\;^{2-}\;3.584 mg/m^3,\;NO_3^-\; 2.803 mg/m^3,\;Cl^-\;1.485 mg/m^3\;and\;NH_4\;^+\;0.998 mgg/m^3$ in precipitation. The annual wet deposition amount of the major ions was shown to be $SO_4^{2-}\;3.865g/m^2/yr,\;NO_3^-\;2.924g/m^2/yr,\;Cl^-\;2.773g/m^2/yr\;and\; NH_4\;^+\;1.485 g/m^2/yr$ during this study period. The seasonal averaged pH in leaves were spring pH 5.9 0.5, summer pH 5.5 0.4 and fall pH 5.1 0.3. The seasonal average water soluble sulfur content in leaves were spring 0.012 0.004%, summer $0.012\;0.002\%\;and\;fall\;0.020\;0.007\%$. The seasonal average water soluble sulfur content in bark were spring $0.0071\;0.0003\%,\;summer\; 0.0066\;0.0004\%,\;fall\;0.0063\;0.0004\%\;and\;winter\;0.0071\;0.0003\%$.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.1
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• pp.8-12
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• 1985

In the pure Phragmites communis grassland in the lower course of Nakdong river, the seasonal changes of standing crop and productive structure, annual changes of the maximum standing crop, and annual net production were estimated. The maximum standing crop of the pure P. communis grassland is on mid-September, the maximum average daily productivity was $32.7g/m^2/day$ from June to July. The leaf area index of the pure reed grassland increased to July, and then decreased slowly. The logitudinal growth of above-ground parts of the reed grassland was maximum state, 320cm, on mid September. Annual net production was $3,399g/m^2/year$, and it suggests that grassland is stable. Productive structure of the pure reed grassland indicated that the distribution of leaf was concentrated on the upper parts according to the grassland maturation.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.421-430
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• 1997

This experiment was conducted to detect the presence of allelopathic substances in the leaves of Ginkgo biloba L. Water extracts from G. biloba leaves which collected at different season markedly inhibited the germination and growth of O. sativa, E. crus-galli, D. sanguinalis, and L. sativa, indicating the presence of biological substances. Linolenic and palmitic acid were the major fatty acids of G. biloba leaves. The biochemical substances such as salicylic arid, p-coumaric acid, catechol, hydroquinone, orchinol, ferulic acid, phloroglucinol, and umbelliferone etc., belonging to the phenolic, compounds were, detected in a large amount, which may be responsible for exhibition inhibitory effects. The common phenolic compounds were detected in the early-harvested and late-harvested G. biloba leaves were salicylic and p-coumaric acid. All these compounds were related to the allelopathic activities in G. biloba leaves.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.4
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• pp.192-203
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• 2018

The surfgrass Phyllospadix iwatensis is native in the exposed rocky shores of the Northwestern Pacific Ocean. In Korea, P. iwatensis is mainly found on the rocky subtidal zone in the central eastern coast. In this study, to examine the ecological characteristics of P. iwatensis, we investigated changes in morphological characteristics, density, biomass, and leaf productivity as well as changes in the underwater irradiance and water temperature of its habitat monthly from August 2017 to July 2018. Underwater irradiance and water temperature showed clear seasonal changes; increases in spring and summer and decreases in fall and winter. Morphological characteristics, shoot density, biomass, and leaf productivities of P. iwatensis exhibited significant seasonal variations, increasing in winter and spring and decreasing in summer and fall months. P. iwatensis leaf productivities both per shoot and per unit area showed significant positive correlations with underwater irradiance. The average leaf productivity of P. iwatensis per area was $6.3{\pm}1.3g\;m^{-2}d^{-1}$, while minimum and maximum values were $2.4{\pm}0.3g\;m^{-2}d^{-1}$ in February 2018 and $16.4{\pm}4.4g\;m^{-2}d^{-1}$ in May 2018, respectively. The optimum water temperature for the growth of P. iwatensis in this study was between $12-13^{\circ}C$.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.1055-1066
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• 2018

Vegetation indices on the basis of optical characteristics of vegetation can represent various conditions such as canopy biomass and physiological activity. Those have been mostly developed with the large-scaled applications of multi-band optical sensors on-board satellites. However, the sensitivity of vegetation indices for detecting vegetation features will be different depending on the spatial scales. Therefore, in this study, the investigation of photochemical reflectance index (PRI), known as one of useful vegetation indices for detecting photosynthetic ability and vegetation stress, under the three spatial scales was conducted using multi-spectral camera installed in unmanned aerial vehicle (UAV),field spectrometer, and leaf reflectometer. In the leaf scale, diurnal PRI had minimum values at different local-time according to the compass direction of leaf face. It meant that each leaf in some moment had the different degree of light use efficiency (LUE). In early growth stage of crop, $PRI_{leaf}$ was higher than $PRI_{stands}$ and $PRI_{canopy}$ because the leaf scale is completely not governed by the vegetation cover fraction.In the stands and canopy scales, PRI showed a large spatial variability unlike normalized difference vegetation index (NDVI). However, the bias for the relationship between $PRI_{stands}$ and $PRI_{canopy}$ is lower than that in $NDVI_{stands}$ and $NDVI_{canopy}$. Our results will help to understand and utilize PRIs observed at different spatial scales.