• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.228-228
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• 2017

Rice production and quality could be changed by temperature condition. Extremely high temperature event have been occurred more frequently for global warming. To increase rice quality against to global warming, breeding of heat tolerance rice cultivar is needed. Ilmi which is the one of Korean leading rice cultivar shows heat stress resistant character during ripening stage. Yield and quality (brown and milled rice) of Ilmi did not show significant different under high temperature condition compared to control condition. However, the main physiological characters for heat resistance of Ilmi have been not investigated yet. Therefore we try to investigate the heat tolerance characters of Ilmi. Two rice cultivars, Ilmi and Ilpum-which is heat susceptible rice cultivar, were cultivated under natural condition in wagnor pot until heading was appeared. After checking heading date, each material was cultivated under different temperature condition, heat($32/22^{\circ}C$) and control($26/16^{\circ}C$) condition. Anti-oxidant enzyme activity was checked during ripening stage in each material. Catalase and ascorbic peroxidase activity of leaf under heat stress condition were higher in Ilmi than Ilpum especially early ripening stage. Analyzing of stress resistance using $H_2O_2$, the flag leaf of Ilmi showed more green color than Ilpum with higher chlorophyll content than those of Ilpum. We also checked the amount of $H_2O_2$ content in young leaf of each material by treating high temperature. $H_2O_2$ content in each material was increased according to treatment time. However $H_2O_2$ content of young leaf in Ilmi was less than those in Ilpum. Also catalase and ascorbic peroxidase activity in leaf increased much faster in Ilmi than Ilpum. With those data, we confirmed that heat stress resistance of Ilmi is due to the higher anti-oxidant activity against to stress condition. We will investigate the heat tolerance characters of Ilmi more in further study to enhance the breeding effect of heat stress tolerance rice.

• Fisheries and Aquatic Sciences
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• v.4 no.3
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• pp.112-119
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• 2001

Aim of this research is to investigate the effect of temperature shocks on the physiological responses of cultured olive flounder (Paralichthys olivaceus) and black rockfish (Sebastes schlegeli). Olive flounder and black rockfish were suffered with high and low temperature shocks for 4 and 8h, respectively, in laboratory conditions and then the changes in glucose, lactate, total protein, uric acid, and triglycerides-glycerol in blood plasma were analyzed. We observed that lactate and uric acid increased for up to 4h and then decreased for up to 8h by the high and low temperature shocks, and total protein decreased for up to 4h and then recovered for up to 8h by the high temperature shock in both fishes. Glucose by the high and low temperature shocks and triglycerides-glycerol by the low temperature shock increased for up to 4h, and then decreased in olive flounder, but increased for up to 8h in black rockfish. From the result, we speculated that the two fishes have an interspecific variation in the regulatory systems of glucose and triglycerides-glycero1. Glucose would play important role as an energy source during the temperature shocks and for an intermediate substance for low temperature tolerance, and glycerol of triglycerides-glycerol would play an important role for low temperature tolerance. In olive flounder, the turnover of chemical change by temperature shock took more than 4h, all chemicals returned almost to the initial level for up to 8h, but fish death followed only in 8h with the high temperature shocked group within two days. Therefore, we suggested that fish would be damaged severely by the longer time exposure of high temperature and mortality would occur after a certain time later than the shocked time as a post-effect.

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

• Journal of the Korean Society of Tobacco Science
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• v.1 no.1
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• pp.39-45
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• 1979

Egg masses of the root- knot nematodes ( Meloidogyne incognita, M. arenaria and M. haply) were exposed to two different regimes of soil moisture (459 and 2459) and temperature ( -2$^{\circ}C$ and 33$^{\circ}C$), quite extreme condition in their natural environment, and their survival rate was compared. Three species did not show any difference in the rate when exposed to either soil moisture for 25 days, with the rate in the range of 8.6% to 10.4%. In response to temperature treatment, however, they differed : the best survival rate was obtained from M. incognita at high temperature ( 33"C) and from M, hapla at low temperature (-2$^{\circ}C$) plot. The third species (M. arenaria) was intermediate in both temperature regimes.imes.

• Mycobiology
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• v.49 no.5
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• pp.476-490
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• 2021

Global temperatures are steadily increasing, leading to significant changes in microbial diversity and ecology. In the present study, we isolated high-temperature-growing fungi and fungi-like group (Oomycota) strains from freshwater environments of Korea and identified them based on cultural, morphological, and multilocus phylogenetic analyses. As a result, we introduce Saksenaea (Fungi) isolates as a new species, Saksenaea longicolla sp. nov. and record Phytophthora chlamydospora and P. lagoariana (Oomycota) new to Korea. In the growth experiments, they exhibited high-temperature tolerance, which can grow at 35-40 ℃ but become inactive at 4 ℃ and below. This study confirms the presence of high-temperature-tolerant fungi and oomycetes in Korea and suggests that the Korean climate conditions are changing in favor of these species. This indicates that climate warming is altering microbial distributions in freshwater environments.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.2
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• pp.197-202
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• 2003

The hot climatic conditions prevailing particularly in summer are not conducive to rear these high yielding bivoltine hybrids throughout the year, In order to select efficiently the breeds with high temperature tolerance, it is very important to analyze critically the impact of high temperature on many silk yielding attributes of silkworm races. Keeping the above in view, the present study was undertaken to determine the effect of high temperature $(36 {\pm} 1^{\circ}C)$ and high humidity $(80 {\pm} 5% Relative Humidity)$ on the rearing performance of pure races, foundation crosses, single hybrids and double hybrids of bivoltine silkworm, Bombyx mori L. The robust bivoltine breeds, CSR18, CSR19, 8HT and 5HT, eight foundation crosses, eight single hybrids and eight double hybrids involving these breeds were chosen as materials in this study.

• Journal of fish pathology
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• v.16 no.2
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• pp.119-123
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• 2003

We have selected an valuable pmbiotic strain; Lactobacillus sakei BK19 which has wide antagonic spectrum against fish pathogens . Present study investigated cultural characterization of L. sakei BK19 including pH tolerance , susceptibility of antibacterial agents and growth pattern with different environment such as nutritions, temperature and salinity. L. sakei BK19 showed Significantly higher resistance at low pH(around pH 4) environment and relative high antibiotic tolerance . In the study of optimal culture condition, maltose and saccharose provided the optimal nutritional culture condition while lactose and mannitol were unable to supply its carbon source for the fermentation of L. sakei BK19. Moreover. L. sakei BK19 showed good growth at the temperature range of 15 to $45^{o}C$ und the NaCl concentration of 0 to 7%. Hence, this particular probiotic strain may be benificial both in seawater and fresh weter conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.192-196
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• 2002

This paper describes on the fabrication and characteristics of a metal thin-film pressure sensor based on Cr strain-gauges for harsh environment applications. The Cr thin-film strain-gauges are sputter-deposited onto a micromachined Si diaphragms with buried cavity for overpressure protectors. The proposed device takes advantages of the good mechanical properties of single-crystalline Si as diaphragms fabricated by SDB and electrochemical etch-stop technology, and in order to extend the operating temperature range, it incorporates relatively the high resistance, stability and gauge factor of Cr thin-films. The fabricated pressure sensor presents a low temperature coefficient of resistance, high-sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.097~1.21 $mV/V{\cdot}kgf/cm^2$ in the temperature range of $25{\sim}200^{\circ}C$ and the maximum non-linearity is 0.43 %FS.

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.229-237
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• 1987

To determine the characteristics of heterotrophic bacterial community in estuarine ecosystem, water and sediment samples were taden from Naktong estuary. All isolates were compared with 73 characters and described by cluster analysis. With same characters, 30 reference strains were able to divide into approximate species level at 80% similarity (S value). Diversity indices ($H^{1}$) of sediment column isolates were higher than water column isolates. The bacterial community commonly appeared in water and sediment column was reduced with going to downstream. Tolerance indices for temperature (Pt) and salinity (Ps) were also higher in sediment isolates than in water isolates. The bacterial community in sediment column is believed to be composed with diverse populations compared to water column and maintains its stability against various environmental changes with high physiological tolerances.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.268-273
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• 2016

Potassium is well-known to improve turfgrass tolerance to environmental stresses such as low temperature and drought stress. Low mowing height reduces leaf area of turfgrass that is main place for photosynthesis and carbohydrate production. Closely-mowed turf would suffer from summer decline by low level of carbohydrate resulted from low photosynthesis of reduced leaf area. The objective of the study is to investigate K rate and mowing height for Kentucky bluegrass. The K rate treatments were 5, 10, and $20g\;K_2O\;m^{-2}$ for the low, medium and high K rates, respectively. The bi-weekly mowing treatment was made for treatments. Mowing was implemented at 40 and 100 mm using a rotary mower. Regardless K rates, the high mowing height would be required when the air temperature is higher than $28.5^{\circ}C$ and high turfgrass quality of Kentucky bluegrass is needed. When the air temperature is optimal for cool-season grass, the high mowing height and the low K rate is needed for the root length of Kentucky bluegrass.