• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.83-89
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• 2001

This study was conducted to test the Cd accumulation and Cd-tolerance of Pisotithus tinctorius(Pt). Pt was isolated from Pinus thunbergii forest in Muan, Chonnam Province in 1997. Pt was cultured on MMN medium supplemented with $CdSO_4{\cdot}5H_2O$ at the final concentration of 0, 0.2, 0.5, 2, and $10{\mu}g/m{\ell}$ for 40 days. Growth rate and tolerance index of the fungus were measured every week, while Cd concentration, superoxide dismutase(SOD), and glutathione reductase(GR) of the fungus were analyzed at the end of the culturing, Pt showed growth reduction in vitro at $2{\mu}g/m{\ell}$ Cd in the medium and almost stopped growth at $10{\mu}g/m{\ell}$ Cd. Tolerance index of Pt decreased with increasing Cd concentration. Cd concentration of Pt was the highest at $10{\mu}g/m{\ell}$ Cd. Activities of SOD did not show significant difference between Cd concentrations, but GR of Pt increased at $0.5{\mu}g/m{\ell}$ Cd, and decreased at $2{\mu}g/m{\ell}$ Cd. Consequently Pt could be called Cd accumulator with a tolerance mechanism to Cd. Their tolerance to Cd were expressed through the higher production of antioxidants such as GR. Pt may be used for revegetation and decontamination of soil polluted by heavy metals.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.613-621
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• 2022

The study aim was to investigate changes in the diameter, number of standing trees, stand volume per ha and site index by the forest survey order, climate zone (northern temperate, central temperate, southern temperate, and warm temperate regions), and altitude in 100 m intervals) by collecting samples of Robinia pseudoacacia from the fifth, sixth, and seventh national forest survey datasets. The rotation cutting age, which is a standard used for wood, was calculated. The changes were statistically analyzed by performing ANOVA and the Duncan multiple test. Diameter growth naturally increased according to the forest survey order and was lowest in the southern temperate region by climate zone and lowest at the 301-400 m altitude. The number of standing trees per ha did not change according to the forest survey order and altitude, and the density was highest in the central temperate region and lowest in the southern temperate region. The stand volume per ha increased according to the forest survey order, and the climate zone was divided into two groups: ① northern temperate region and central temperate region, ② southern temperate region and warm temperate region. The stand volume growth was highest at the 201-300 m point. Thesite index showed results similar to the change pattern of the stand volume per ha. The growth curve, which can be seen by the change in stand volume per ha, was estimated by applying theWeibull formula, and the stand volume per ha was estimated to reach approximately 200 m³/ha at 50-60 years. The rotation of the highest production in volume, which is the standard for using trees as wood rather than honey sources, was calculated to be 34 years.

• Journal of Mushroom
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• v.21 no.1
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• pp.22-32
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• 2023

To investigate the effect of thinning intensity on environmental factors and ectomycorrhizal mushroom fruiting in forest ecosystems, we studied canopy closure, throughfall, soil temperature, soil moisture, light response of understory vegetation, and ectomycorrhizal mushroom fruiting in a 10-year-old pine forest after 34%, 45%, and 60% thinning. Canopy closure was significantly higher in the 34% treatment and control plots, ranging from 80-85% in April. However, in November, all thinning treatment plots showed a decrease of approximately 5-10% compared with the control plot. The 60% treatment plot had over 200 mm of additional throughfall compared with the control plot, and monthly throughfall was significantly higher by more than 100 mm in October. The soil temperature in each treatment plot increased significantly by up to 1℃ or more compared with the control plot as the thinning rate increased. The soil moisture increased by more than 5% in the thinning treatment plots during rainfall, particularly in the 34% treatment plot, where the rate of moisture decrease was slower. The photosynthetic rate of major tree species (excluding Pinus densiflora)was highest in Quercus mongolica, with a rate of 7 µmolCO₂·m^-2·s^-1. At a lightintensity of 800 μmol·m^-2·s^-1, Q. mongolica showed the highest photosynthetic level of 6 ± 0.3 μmolCO₂·m^-2·s^-1 in the 45% treatment. The photosynthetic rate of Fraxinus sieboldiana and Styrax japonicus increased as the thinning intensity increased. The Shannon-Wiener index of mycorrhizal mushrooms did not significantly differ among treatments, but the fresh weight of mushrooms was approximately 360-840 g higher in the 34% and 45% treatments than in the control. Additionally, the fresh weight of fungi in the 60% treatment was 860 g less than that in the control. There were more individuals of Amanita citrina in the control than in the thinning treatment, while Suillus bovinus numbers increased by more than 10 times in the 34% thinning treatment compared with the control.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.157-164
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• 2023

Codonopsis lanceolata (S. et Z.) Trautv. is mainly cultivated in Korea and China as a medicinal crop. C. lanceolata is difficult to produce plug seedlings in the summer, because C. lanceolata has a low germination rate and is vulnerable to high temperatures. Cold treatment is effective in breaking dormancy of seeds and increasing the germination rate. Shading cultivation can control the solar irradiance received by plants and reduce the damage by high temperatures and strong light. This study was conducted to examine the appropriate cold treatment period for the improving germination of C. lanceolata, and shading level during the summer seedling period. Cold treatment experiments were conducted for 0 (control), 1, 2, 3, and 4 weeks at 4℃ before sowing. In the shading experiment, C. lanceolata was grown for 45 days with 0 (non-treatment), 45, 75% shading levels. Cold treatment for one week significantly improved the germination energy. The plant height, leaf area, and fresh and dry weights of C. lanceolata seedlings were significantly increased under the 45% shading level. Total root length, root surface area, and the number of root tips were significantly higher in shading treatment (45 and 75%) than in non-treatment. The C. lanceolata seedling's compactness and Dickson's quality index were the highest at 45% shading level. Therefore, these results recommended sowing C. lanceolata after cold treatment for one week at 4℃, and 45% shading level could stably culture C. lanceolata plug seedlings during the high temperature period.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1635-1650
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• 2023

Under global warming, the steadily increasing sea surface temperature (SST) severely impacts marine ecosystems,such as the productivity decrease and change in marine species distribution. Recently, the catch of Todarodes Pacificus, one of South Korea's primary marine resources, has dramatically decreased. In this study, we analyze the marine environment that affects the formation of fishing grounds of Todarodes Pacificus and develop seasonal habitat suitability index (HSI) models based on various satellite data including Geostationary Ocean Color Imager (GOCI) data to continuously manage fisheries resources over Korean exclusive economic zone. About 83% of catches are found within the range of SST of 14.11-26.16℃,sea level height of 0.56-0.82 m, chlorophyll-a concentration of 0.31-1.52 mg m^-3, and primary production of 580.96-1574.13 mg C m^-2 day^-1. The seasonal HSI models are developed using the Arithmetic Mean Model, which showed the best performance. Comparing the developed HSI value with the 2019 catch data, it is confirmed that the HSI model is valid because the fishing grounds are formed in different sea regions by season (East Sea in winter and Yellow Sea in summer) and the high HSI (> 0.6) concurrences to areas with the high catch. In addition, we identified the significant increasing trend in SST over study regions, which is highly related to the formation of fishing grounds of Todarodes Pacificus. We can expect the fishing grounds will be changed by accelerating ocean warming in the future. Continuous HSI monitoring is necessary to manage fisheries' spatial and temporal distribution.

• Korean Journal of Agricultural and Forest Meteorology
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• v.26 no.2
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• pp.89-102
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• 2024

Land Surface Phenology (LSP) plays a crucial role in understanding vegetation dynamics. The near-infrared reflectance of vegetation (NIRv) has been increasingly adopted in LSP studies, being recognized as a robust proxy for gross primary production (GPP). However, NIR v is sensitive to the terrain effects in mountainous areas due to artifacts in NIR reflectance cannot be canceled out. Because of this, estimating phenological metrics in mountainous regions have a substantial uncertainty, especially in the end of season (EOS). The topographically corrected NIRv (TCNIRv) employs the path length correction (PLC) method, which was deduced from the simplification of the radiative transfer equation, to alleviate limitations related to the terrain effects. TCNIRv has been demonstrated to estimate phenology metrics more accurately than NIRv, especially exhibiting improved estimation of EOS. As the topographic effect is significantly influenced by terrain properties such as slope and aspect, our study compared phenology metrics estimations between south-facing slopes (SFS) and north-facing slopes (NFS) using NIRv and TCNIRv in two distinct mountainous regions: Gwangneung Forest (GF) and Odaesan National Park (ONP), representing relatively flat and rugged areas, respectively. The results indicated that TCNIR v-derived EOS at NFS occurred later than that at SFS for both study sites (GF : DOY 266.8/268.3 at SFS/NFS; ONP : DOY 262.0/264.8 at SFS/NFS), in contrast to the results obtained with NIRv (GF : DOY 270.3/265.5 at SFS/NFS; ONP : DOY 265.0/261.8 at SFS/NFS). Additionally, the gap between SFS and NFS diminished after topographic correction (GF : DOY 270.3/265.5 at SFS/NFS; ONP : DOY 265.0/261.8 at SFS/NFS). We conclude that TCNIRv exhibits discrepancy with NIR v in EOS detection considering slope orientation. Our findings underscore the necessity of topographic correction in estimating photosynthetic phenology, considering slope orientation, especially in diverse terrain conditions.

• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.265-271
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• 2004

A feeding trial was conducted to investigate the influence of feeding Lactobacillus reuteri culture (LR) on productive performance, intestinal microflora and availability in laying hens. Four hundred and eighty, Isa-Brown layers, 49 weeks of age, were fed diets supplemented with LR at the level of 0 (control), 0.1, 0.2, and $0.4\%$ of the diets for eight weeks. Egg production and egg weight were measured daily. Feed intake was weighed every two weeks. Egg quality was measured three times at the start, mid-term, and end of the experiment. Intestinal microflora were examined for Lactobacillus spp., E. coli and Salmonella at the end of the experiment. Overall egg production was the highest in $0.2\%$ LR (P<0.05), but that of $0.1\%$ or $0.4\%$ LR treatments did not significantly differ from that of control. Egg weight was significantly higher in LR feeding group than the control (P<0.05). Daily egg mass was significantly higher in $0.2\%$ and $0.4\%$ LR treatments compared to the control and $0.1\%$ LR (P<0.05). The number of jumbo and extra large eggs were increased in LR supplemented groups, especially in $0.1\%$ LR. Feed intake of layers fed LR supplemented diets tended to be lower than the control. However, feed conversion ratio significantly improved in LR supplemented groups (P<0.05). Availability of dry matter and crude protein improved significantly in $0.4\%$ LR treatment (P<0.05). But, those of ether extract and crude ash were not significantly different among treatments. Eggshell breaking strength and eggshell thickness were not significantly influenced by LR supplementation, and Haugh unit and yolk index were also similar to the control. Total number of Lactobacillus spp. in ileum and cecum fed LR supplemented diets were significantly higher than those of the control (P<0.05). There were no significant differences in intestinal E. coli and Salmonella in all treatments. Therefore, it is concluded that dietary supplementation of Lactobacillus reuteri culture can improve the laying performance, feed efficiency and intestinal Lactobacillus.

• Korean Journal of Environmental Agriculture
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• v.8 no.2
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• pp.128-135
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• 1989

To find the effects of solar energy into the rice canopy and its balance on the rice plant growth, a Tongil type rice, Raekyeong and a japonica rice, Koganebare were used with four levels of nitrogen fertilizer application, 6, 10, 14, and 18kg $l0a^{-1}$ in Chigugo, Japan. The micrometerosological data, the solar radiation and absorbed solar radiation by the rice plants, and leaf area index on cardinal growth stage of the rice community were measured. The results are as follows : Raekyeong showed increased LAI by increased nitrogen fertilizer application rates, and larger LAI than Koganebear. 1. There was no difference in total dry weight till 20 days after transplanting regardless of nitrogen levels in the same variety, after that, however, Raekyeong showed higher dry matter productions for the same durations than Koganebare. 2. In early growth stage of transplanting rice, reflection ratio of solar radiation above the crop canogy was about 6%, however, it was increased up to 20% by the increased LAI at heading date. 3. In high levels of nitrogen application plots, LAI were increased so that values were decreased. 4. Relationship between the amount of absorbed radiation by plants and its dry matter production was linearly significant. Higher levels of nitrogen application produced higher dry matter in Raekyeong, however, in lower level, the dry matter production pattern was almost similar between both rice cultivars.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.356-362
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• 2015

Prickly pear cactus cladodes were extracted with hot water and 70% ethanol, followed by fractionation with n-hexane (HF), ethyl acetate (EF), n-butanol (BF), and distilled water. Total phenolics and total flavonoid contents as well as antioxidative and anti-inflammatory activities were then measured. Total phenolic contents were 784, 452, and 220 mg gallic acid equivalents (GAE)/g, whereas total flavonoid contents were 214, 76, and 113 mg quercetin equivalents (QE)/g in EF, BF, and HF, respectively. DPPH and ABTS radical scavenging activities ($IC_{50}$) were 103 and $105{\mu}g/mL$ in EF, 359 and $379{\mu}g/mL$ in BF, and 469 and $605{\mu}g/mL$ in HF, respectively. Oxygen radical absorbance capacity was highest at $391{\mu}M$ TE in EF (in decreasing order of $117{\mu}M$ TE in BF and $64{\mu}M$ TE in HF), whereas superoxide anion radical scavenging activity ($IC_{50}$) was highest at $40{\mu}g/mL$ in EF (in decreasing order of $69{\mu}g/mL$ in BF and $98{\mu}g/mL$ in 70% ethanol extract). Inhibitory activity ($IC_{50}$) of nitric oxide (NO) production induced by LPS-activated RAW264.7 cells was highest at $62{\mu}g/mL$ in HF (in decreasing order of $104{\mu}g/mL$ in EF and $465{\mu}g/mL$ in BF). The selectivity index (ratio of inhibitory activity of NO production to cell cytotoxicity) was highest at 4.63 in EF (in decreasing order of 3.37 in HF and 2.14 in BF). In conclusion, EF showed potent antioxidant and anti-inflammatory effects with high phenolic and flavonoid contents.

• Journal of Gastric Cancer
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• v.5 no.4 s.20
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• pp.238-245
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• 2005

Purpose: Ghrelin, produced primarily in the gastrointestinal tract, including the stomach, has been reported to reflect nutritional status and to control homeostasis by influencing food intake and adiposity. The purpose of this study is to evaluate nutritional status, as well as plasma and gastric tissue ghrelin levels, in patients with gastric cancer who underwent a gastrectomy. Materials and Methods: Eighty patients were analyzed by the degree of weight loss $(weight\;loss{\geq}5%\;or\;<5%)$ and the extent of gastrectomy (subtotal or total gastrectomy). Blood samples were collected from all patients preoperatively and postoperatively especially at seven days. Gastric tissues, including tumor and normal tissues, were obtained from the resected stomach. levels of plasma and tissue ghrelin were measured with a commercial ELISA kit. Results: There were no significant differences in the clinical characteristics and ghrelin levels of plasma, gastric tumor tissue and normal tissue by the degree of weight loss. The ghrelin levels in plasma and tumor tissue showed no correlations with each other while the ghrelin level in tumor tissue was significantly lower than that in normal tissue. The degree of cellular differentiation also had an association with ghrelin production. A gastrectomy proved to decrease significantly plasma ghrelin levels, body mass index, and biochemical markers, regardless of the extent of gastric resection. Conclusion: These results show that gastric cancer affects the production of ghrelin in the gastric mucosa and that ghrelin is mainly produced in stomach even though it could be partially covered by endogenous ghrelin from other organs following a gastrectomy. However, we should further investigate which other factors have an impact on energy consumption, ghrelin secretion, and changes in ghrelin levels after a gastrectomy.