• Korean Journal of Agricultural and Forest Meteorology
• /
• v.3 no.3
• /
• pp.135-142
• /
• 2001

This study attempts to categorizes the factors of forest fire occurrences based on regional meteorologic data and general forest no characteristics of 18 cities and guns in Kangwon province. lo accomplish this goal, some statistical analyses such as analysis of variance, correspondence analysis and multidimensional scaling were adopted. To reveal the forest fires pattern of study region, a categorization process was conducted by employing the quantification approach which modified and quantified the metric-data of fire occurrence dates. Also, The fire occurrence similarity was compared by using multidimensional scaling for each study region. The major results are summarized as follows: It was found that the meteorological factors emerged as different to each region are average and maximum temperature, minimum dew point temperature and average and maximum wind speed. In the result of correspondence analysis representing relationships between fire causes and study regions, Kangrung is caused by arsonist, Chulwon, Hwachen and Yanggu caused by military factor, Sokcho and Chunchen caused by the debris burning, and Samchuk caused by general man-caused fires, respectively. Finally, the forest fire occurrence pattern of this study regions were divided into five areas such as, group I including Samchuk, Kangryung, Chunchen, Wonju, Hongchen and Hhoingsung, group II including Donghae, Taebaek, Yangyang and Pyongchang, group III including Jungsun, Chulwon and Whachen, group Ⅵ including Gosung, Injae and Yanggu, and group V including Shokcho and Youngwol.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.10 no.1
• /
• pp.17-24
• /
• 2008

This study was performed to estimate non-$CO_2$ greenhouse gases (i.e., GHGs) emission from biomass burning at a local scale. Estimation of non-$CO_2$ GHGs emission was conducted using Landsat TM satellite imagery in order to assess the damage degree in burnt area and its effect on non-$CO_2$ GHGs emission. This approach of estimation was based on the protocol of the 2003 IPCC Guidelines. In this study, we used one of the most severe fire cases occurred Samcheock in April, 2004. Landsat TM satellite imageries of pre- and post-fire were used 1) to calculate delta normalized burn ratio (dNBR) for analyzing burnt area and burn severity of the Samcheok large-fire and 2) to quantify non-$CO_2$ GHGs emission from different size of the burnt area and the damage degree. The analysis of dNBR of the Samcheok large-fire indicated that the total burnt area was 16,200ha and the size of the burnt area differed with the burn severity: out of the total burnt area, the burn severities of Low (dNBR < 152), Moderate (dNBR = 153-190), and High (dNBR = 191-255) were 35%, 33%, and 32%, respectively. It was estimated that the burnt areas of coniferous forest, deciduous forest, and mixed forest were about 11,506ha (77%), 453ha (3%), and 2,978ha (20%), respectively. The magnitude of non-$CO_2$ GHGs emissions from the Samcheok large-fire differed significantly, showing 93% of CO (44.100Gg), 6.4% of CH4 (3.053Gg), 0.5% of $NO_x$ (0.238Gg), and 0.1% of $N_2O$ (0.038Gg). Although there were little changes in the total burnt area by the burn severity, there were differences in the emission of non-$CO_2$ GHGs with the degree of the burn severity. The maximum emission of non-$CO_2$ GHGs occurred in moderate burn severity, indicating 47% of the total emission.

• Korean Journal of Animal Reproduction
• /
• v.25 no.2
• /
• pp.125-130
• /
• 2001

This study was performed to report a direct dose dependent stimulatory effect of the Flavonoid(F) on basal testosterone secretion and a dose dependent effect on LH induced testosterone production by Leydig cell of matured rats in vitro culture. F was obtained kom the Rhus vernicifua through aceton extraction and silica gel adsorption column chromatography. Leydig cells (1$\times$10$^{6}$ cells/well) from 12 weeks old rats were incubated with or without F(0, 20, 40, 80, 160 ng) or insulin-like growth factor-I(IGF-I) in the presence or absence of LH(10, 100ng). 1. The maximal stimulatory concentrations of testosterone in culture media were showed at 24hr of culture. but these testosterone level were decreased at 36 hr of culture. 2. Flavonoid(80ng) were significantly(P ＜ 0.05) increased testosterone production compared with control groups for 12 hr culture. 3. Testosterone secretion by Leydig cells stimulated with LH(10, 100ng) for 6 hr and 12hr culture compared with 3 hr culture. 4. LH 10 ng augmented testosterone were increased by addition of F 40 ng for 12 hr culture. 5. F(0 and 40 ng) also enhanced LH 10 ng stimulated testosterone for 3 hr Leydig cells culture. 6. Addition of IGF-I 100 ng to the culture medium for 6 hr were increased the concentration of testosterone by Leydig cells stimulated with 100 ng LH. These results indicate that Flavonoid has a direct stimulatory effect on basal testosterone secretion in rat Leydig cells, and also modulates LH mediated testosterone. Therefore, Flavonoid may act as a modulator on gonadal development or gonadal steroidogenesis in direct or indirect.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.29 no.4
• /
• pp.376-385
• /
• 1984

The habit of anthesis and maturity of sesame were investigated as a basic research for the improvement of high-yielding varieties and cultural practices. Eight different plant types were identified using typical cultivars among gene pool grown in Korea. Non-branching, Monocapsule, Bicarpels quadriloculi (NMB) type showed higher ratio for capsule setting compared with Non-branching, Monocapsule, Quadricarpels octoloculi (NMQ) type. Non-branching, Tricapsules, Quadricarpels octoloculi(NTQ) type presented lower ratio for capsule setting than non-branching, tricapsules, bicarpels quadriloculi(NTB) type. The number of flowers by flower setting position was the highest on lower part, intermediate on middle part, and the lowest on higher part in NMB and NTB type. However, the number of flowers was the highest on middle part, intermediate on lower part, and lowest on higher part in NMQ and NTQ type. BMB type appeared to have the highest ratio for capsule setting when compared with the other plant types. BTB type with many flowers and capsules exhibited higher percentage for capsule setting than BTQ type with lowest capsule setting percentage. Capsule setting percentage of branch appeared to be lower than that of main stern in the branching type. The branching type had more flowers and capsules than non-branching type. Tricapsules type had more flowers and capsules per plant than monocapsule type, and bicarpels quadriloculi type had more than quadricarpels octoloculi type. However, capsule setting ratio in non-branching type was higher than in branching type. The ratio was higher in monocapsule type than in tricapsules type. Bicarpels quadriloculi type had higher ratio of capsule setting than quadricapels octoloculi type. Number of capsules per plant and capsule setting ratio are supposed to be dominated by shape of capsule (number of carpels and loculi), not by branching or number of capsules per axil. The order of number of capsules per plant was as follows; BTB, BMB, NTB, BTQ, BMQ, NTQ, NMQ, and NMB types. However, the order of capsule setting ratio was as follows: BMB, NMB, NTB, NTQ, NMQ, BMQ, BTB, BTQ types. Consequently, branching, tricapsules, bicarpels quadriloculi(BTB) type was considered as a sourse of breeding for high yielding varieties by introducing the genes govering BMB type with one capsule per axil which has high capsule setting ability.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.36 no.5
• /
• pp.429-444
• /
• 1991

Cold stress influence plant growth through a wide range of growth characters. Adverse effects of low temperature to plant growth come from results of colligative and complex physiological responses to cold stress. To evaluate more exactly cold tolerance of crop plant, it is needed to observe physiological changes induced by cold stress and to analyze relationships between intraspecific variations in physiological factors related to cold tolerance and the extent of cold tolerance in the field. Therefore, the composition and unsaturation ratio of fatty acids in phospholipid, a constituent of membrane, the transition-temperature in respiratory activity of mitochodria, the chlorophyll fluorescence as a factor related to photosynthesis were investigated in rice plant and data on these factors were compared with the degree of cold tolerance obtained in the field experiment. Also, effects of hardening and Mn++ treatment were evaluated as a method to reduce chilling injuries. The unsaturation ratio of fatty acids, whether rice plants were grown in a natural condition or under the chilling stress, was higher in the cold- tolerant varieties and was significantly correlated with the degree of cold tolerance (1-9) observed in the field experiment. And it was also increased by chilling treatment or hardening treatment, due to a reduction in palmitic acid content and an increase in linolenic acid content. The transition-temperature of respiratory activity of mitochodria isolated from etiolated rice seedlings ($25^{\circ}C$, two week-grown in the dark), was correlated with the degree of cold tolerance in the field, cold -tolerant varieties showing a lower transition-temperature. It was not influenced by growth stages. The intensity of chlorophyll fluorescence was highly correlated with the degree of cold tolerance, cold-tolerant varieties having a higher fluorescence intensity. By foliar application of Mn, the transition-temperature of respiratory activity was lowered as much as 0-2$^{\circ}C$ in all tested varieties. Soil application of Mn induced more significant effect in cold-susceptible varieties with a possibility of reducing chilling injuries. On the whole, there were high correlationships among the degree of cold tolerance, the unsaturation ratio of fatty acids in phospholipid, the transition- temperature of respiratory activity and chlorophyll fluorescence except for a few varieties. The transition- temperature of respiratory activity appeared to be negatively correlated with the unsaturation ratio of fatty acids. and the chlorophyll fluorescence to be positively correlated with the unsaturation ratio. This implies that these physical and physiological factors were very closely related to cold tolerance and can be used as an effective index of the evaluation of cold tolerance of crop plant. But other factors as well as three factors discussed above are needed to be considered colligatively and altogether with a systematic analysis for the more exact evaluation of cold tolerance. in rice cultivars. in rice cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.3
• /
• pp.285-296
• /
• 1995

Anatomical studies of sink tissues are required for better understanding the biological plant growth system and energy metabolism. Kinematics of root growth zones of two genotypes of tall fescue (Festuca arundinacea Schreb.) receiving 50 or 200 ppm N were determined. Longitudinal anatomy and cell dynamics of root growth zones were studied and calculated. The root growth zone is organized similarly to the leaf growth zone which has cell division, elongation, and maturation zones, but the root growth zone is only about 3.0 mm long compared to 25 to 30 mm for the leaf growth zone. The root cap extends about 0.4 to 0.5 mm from the apical initial, while the cell elongation zone for both cortical and metaxylem cells extends about 3.3 mm from the apical initial for both genotypes and N levels. Root cap cells elongate from an initial length of about 5$\mu{m}$ long to a final length of about 40$\mu{m}$ before being sloughed. Initial lengths of cortical and metaxylem cells were about 8.5 $\mu{m}$ and 13.0 $\mu{m}$, respectively. Elongation of cortex and metaxylem cell showed sigmoidal curves with final lengths of about 120 $\mu{m}$ for cortex cells and 650 $\mu{m}$ for metaxylem cells. Initial size and final size for both types were not affected by N level, but cell fluxes and cell elongation rates of cortical and metaxylem cells were about double in low N. Cell production rates were about 5 to 6 times higher in cortical cells than in metaxylem cells. Differences in N caused a larger change in cell production rate, duration of cell elongation, and relative cell elongation rate than did the genotypes. These data indicate that N application affects root growth longitudinally by changing cell production rate and elongation rate.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.52 no.3
• /
• pp.303-310
• /
• 2007

Sweetpotato shoot tops (leaves, tips and petioles) are known to be very useful parts as vegetables because of their high nutritive values and great biomass yield. In this study, the phenolic compound contents, antibacterial activity, mutagenic activity, and antimutagenic activity were investigated in sweetpotato tips that were 10-15cm of shoot top including stems, petioles and tender leaves after sprout of storage roots. The study was done by extracting sweetpotato tips with 80% ethanol and the ethanol fraction was re-extracted with hexane, chloroform, ethyl acetate, butanol and water. In ethyl acetate and butanol fractions, total phenolic compounds contained 95. 6mg/g extract and 69.3 mg/g extract, respectively, The antibacterial activity was measured using the paper disk method with concentrations of 1, 2, 5 and 10 mg/disk of butanol and ethyl acetate fractions against L. monocytogenes and S. Typhimurium strains. Higher doses of solvent extracts showed the higher antibacterial activities. In addition, 5, 10 and 20 mg/mL of the extracts were tested to determine the antibacterial activity in liquid culture. The sweetpotato leaf extract by ethyl acetate showed 1 log reduction compared to control after 24 hrs on Listeria monocytogenes, but 20 mg/ml of butanol extract completely inhibited the growth of the pathogen after 12 hrs. The extracts from ethyl acetate or butanol on Salmonella Typhimurium did less than 1 log reduction during cultivation compared to control. The numbers of S. Typhimirium TA98 and TA100 revertant colonies were 29-33 and 159-188 CFU/plate, respectively, indicating that solvent extracts were no mutagenic activity. The antimutagenic test was performed by adding direct mutagen 2-NF and MMS, and butanol and ethyl acetate showed antimutagenic effect. Thus, this study showed that sweetpotato tips had high phenolic contents and both antimicrobiol and antimutagenic properties. Sweetpotato tips would be good nutritive source because of their high nutrient content without any toxicity in consuming.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.56 no.1
• /
• pp.1-7
• /
• 2011

In this study, we investigated the antioxidant activities, inhibition activity against ACE (angiotensin converting enzyme) and antitumor activity of extract from Acanthopanax senticosus HARMS fruits for development novel functional resources. In order to understand the factors responsible for the potent antioxidant and antihypertensive ability of fruits in A. senticosus, it has been evaluated for anti-oxidative activity using Fenton's reagent/ethyl linoleate system and for free radical scavenging activity using the l,l-diphenyl-2-picryl hydrazyl free radical generating system. The fruits extract of A. senticosus showed higher antioxidant activities than positive control, ${\alpha}$-tocopherol at all concentrations, while fruits extract of A. senticosus showed same degree of radical scavenging activity with positive control, ${\alpha}$-tocopherol. The ability of fruit extracts from A. senticosus to influence the inhibitory activity of angiotensin converting enzyme (ACE) and xanthine oxidase (XOase) has also been discussed. The activity of growth-inhibitory of fruit extracts of A. senticosus was screened by SRB (sulphorhodamine B) method on diverse cancer cells representing different types of cancers. The fruit extracts of A. senticosus showed moderate inhibition on proliferation of LNCaP and MOLT-4F cells and did not inhibit the proliferation of other cancer cells. The fruit extracts of A. senticosus inhibited the proliferation of cancer cells with $GI_{50}$ values ranging from 5 to $10{\mu}g/mL$. This result revealed that the fruit extracts of A. senticosus was expected to be good candidate for development into source of free radical scavengers, antihypertentive, and anti-tumor agent.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.63 no.2
• /
• pp.149-157
• /
• 2018

In this study, we investigated the changes in physicochemical properties, antioxidant activities, and contents of functional compounds, such as avenanthramides (AVNs), vitamin E, and ${\beta}$-glucan, in oats by accelerated age-conditioning (temperature: $45^{\circ}C$, relative humidity: 20%). No significant differences were observed in crude protein, crude fat, and AVNs contents of three oat cultivars, up to 63 days of storage; however, their antioxidant activities, as well as ${\beta}$-glucan, vitamin E, and fatty acid contents were significantly different (p < 0.05). ${\beta}$-glucan and fatty acid contents and the antioxidant activities of Deayang (DY) cultivar did not change during storage. ${\beta}$-glucan and unsaturated fatty acid contents of Choyang (CY) and Jopung (JP) increased during the storage period, while antioxidant activities did not (DPPH-CY; 48.1 to 26.9 mg TEAC/100 g, JP; 49.4 to 26.7 mg TEAC/100 g. ABTS-CY; 88.4 to 56.3 mg TEAC/100 g, JP; 80.0 to 55.8 mg TEAC/100 g). The total vitamin E content in DY (1.20 to 0.85 mg/100 g) and CY (1.73 to 1.33 mg/100 g) decreased, but it was maintained in JP. This study indicated that the changes in physicochemical properties and functional compounds of oat grains during storage depends on the cultivars. The result showed that DY, which has the highest AVNs content, has more stable functional compounds and antioxidant activities during storage. These results can serve as essential data for post-harvest management and development of functional food materials for extending the use of oats.

• Economic and Environmental Geology
• /
• v.35 no.5
• /
• pp.395-406
• /
• 2002

The sixty natural springs and community wells used as a drinking water in the Daejeon area are mainly located at the parks and the natural green districts. The purpose of this study is to investigate the characteristics of water quality and the contamination of the springs and the wells, and to suggest the management strategy for the springs and wells. For this study, we undertook water quality data from Daejeon City. According to the statistic analysis of water quality data, unacceptable rate as a drinking water was about 28 percent in 1999 and 24.5 percent in 2000, respectively. Major unacceptable factor is coliform, and others are bacteria, yersinia, color, turbidity, Fe and F. The unacceptable rate shows a roughly positive relationship with precipitation, that is, it shows highest rate during a rainy season between June and September. The major contamination source is likely to be the excrement of wild animals around natural springs and wells. Most of springs are vulnerable to the contamination of coliform and bacteria because of short residence time and shallow circulation in subsurface environment. The water samples collected from 31 springs or wells show weak acidic pHs, the electrical conductivity ranging from 63 to 357 $\mu\textrm{S}$/cm, and the hydrochemical types of Na(Ca)-HC0$_3$ and Ca-HC0$_3$. The groundwater samples of low total dissolved solid(TDS) belong to Na(Ca)-HC0$_3$. type, and the groundwater of high total dissolved solid is shifted towards Ca-HC0$_3$ type in the chemical composition. These hydrochemical characteristics indicate that most natural springs is in the early stage of geochemical evolution. The natural springs should be closed during a rainy season, which shows a high contamination rate. We suggest that a protection barrier around the springs should be built to keep wild animals away from the springs.