• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.278-278
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• 2022

Recently, the yield potential of high yield Tongil-type rice varieties has greatly increased, reaching 817kg/10a(Geumgang No.1). Moreover, in order to promote rice consumption and strengthen the competitiveness of the rice processing industry, the R&D of high yield Tongil-type rice varieties for each processing purpose, such as rice noodles, grain feed and industrial materials, has been continuously carried out. However, because Tongil-type rice varieties or lines are generally very vulnerable to cold damage, cold tolerance test can be said to be absolutely necessary to improve the cultivation safety. This study is the result of the seedling and field cold tolerance characteristic tests carried out in 2021 of high yield Tongil-type rice breeding lines. For the cold tolerance characteristic test of seedlings, total 303 high yield rice breeding lines for processing were treated in cold water of 13℃ and irrigation depth of 4cm for 10 days from the third-leaf age, then it was evaluated by comparing the degree of discoloration and withering with the checked varieties(Boramchan, Hanahreum No.2). Also, for the test of field, total 186 high yield rice breeding lines for processing were treated in cold water of 17℃ by keeping pouring day and night from 30 days after transplanting to ripening stage, then it was evaluated by comparing the degree of discoloration, delay of heading, shortening rate of stem length and percent of fertile grain etc. with the checked varieties. And the cold tolerance evaluative criteria were classified as strong(1~3), medium(4~6) and weak(7~9) in overall cold tolerance. (Seedling test) As for the degree of cold tolerance of the check variety, 'Boramchan' and 'Hanahreum No.2' showed a response of 'medium' and 'weak', respectively. However, there was no 'strong' line in the high yield rice breeding lines, 2 lines showed a 'medium' response, and 301 lines showed a 'weak' response. Therefore, except for a few lines(0.7%), most lines(99.3%) showed a 'weak' response. (Field test) In terms of the overall cold tolerance of the check variety, both 'Boramchan' and 'Hanahreum No.2' showed a 'medium' response. Similarly, there was no 'strong' line in the case of high yield rice breeding lines, 20 lines showed a 'medium' response, and 166 lines showed a 'weak' response. Therefore, except for some(10.8%) lines, most(89.2%) lines showed a 'weak' response. From the above results, we selected about 100 individuals with less seed shattering and degeneration of the ear tip, and with a relatively high percent of fertile grain, and are continuing to select lines with improved cold tolerance in the F4~F5 group in this year. As such, most of the Tongil-type rice varieties have poor cold tolerance and thus have low cultivation safety at low temperatures. However, it is important to select improved lines through generational progress because there are some lines that still have a certain level of cold tolerance among them.

• 한국작물학회지
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• 제44권2호
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• pp.176-179
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• 1999

Trinexapac-ethyl[ 4-(cyclopropyl- $\alpha$ -hydroxy-methylene)-3,5-dioxocyclohexane carboxylic acid ethylester] is a growth-retardant for plants by inhibiting a key step in biosynthesis of GA. A treatment of trinexapacethyl generally induces a reduction in vegetative growth and also inhibits heading. In addition, the trinexapacethyl was known to enhance the freeze-tolerance in annual bluegrass, however, the mechanism is not known yet. One possible reason for the enhanced freeze-tolerance may be the antifreeze protein known to be accumulated in intercellular space of the leaf during cold acclimation. In order to see the possible in-duction of the synthesis of antifreeze proteins by trinexacpacethyl, the apoplastic proteins extracted from Kentucky bluegrass treated with trinexapacethyl were analyzed by SDS-PAGE and the presence of the antifreeze protein was observed. In addition, western analysis showed the identity of the protein induced by both a cold acclimation and a trinexapacethyl treatment. It appears that an enhanced freeze-tolerance of the turf grass by trinexapacethyl is due to the synthesis and/or accumulation of the antifreeze protein similar to the enhanced freeze tolerance induced by cold acclimation.

• 한국의류학회지
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• 제21권6호
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• pp.1003-1009
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• 1997

To study the time course of increased cold tolerance, the physiological responses were measured during the course of a 2-yr study (Feb. 1995~Feb. 1996) of four female college students, whose cold tolerance was proved to be increased through wearing cool clothing in daily life from Sep. 1994 to Feb. 1995. To determine their cold tolerance, subjects rested at 25$\pm$1$^{\circ}C$, then were exposed to 15$\pm$1$^{\circ}C$, 50$\pm$5% R.H. for 90min in Feb. 1995 and Feb. 1996. Subjects' rectal temperatures, mean skin temperatures, heat production, shivering onset, thermal sensations, and comfort showed no significant changes, when they were measured in 1995 and 1996. Based on these results, we can safely assume that mild cold acclimatization coming from wearing cool clothing lasts at least oneyear, that is until the following year. One of the possible explanations for this is that the subjects did not increase their clothing thermalresistances after the cold acclimatization.

• 한국초지조사료학회지
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• 제20권1호
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• pp.1-6
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• 2000

Improvement of cold-tolerance of Italian ryegrass(Lo1ium multiflorum L.) is an important breeding objectivefor enlargement of cultivation area in Korea. To develop the cold-tolerant variety of Italian ryegrass,cold-tolerant clones survived under - 13- - 14$^{\circ}$C of minimum average air temperature in January wereselected in the area of Dun Nae, Kwangwon Province. The 5 lines of Italian ryegrass clones selected werepolycrossed for seed production. Synthetic seeds were examined on growth characters and forage productionsin Suwon from 1996 to 1998, in Unbong 1997 and in Younchun 1998, respectively. The growth charactersand forage productions of Italian ryegrass variety named as "Hwasan 101" were summarized as follow ;ltalian ryegrass variety, Hwasan 101 was tetraploid and showed semi-prostrate growth habit in autumn andwas not only dark green in leaf color and broad in flag leaf width but also excellent in leafiness. Also, itshowed low plant height at first heading date of 20th May and excellent lodging tolerance. Expecially,Hwasan 101 in all trial regions was 80 -90% of winter survivals that was higher than 60 -90% of Florida80 and Marshall varieties. Therefore we estimate that Hwasan 101 can be cultivated in regions that is higherthan -9$^{\circ}$C in minimum average air temperature and lower than 400m in sea level. In forage production ofHwasan 101, fresh weight and total digestible nutrient(TDN) yield were 66,940 and 6,551kghq and drymatter yield was 10,050kgha. In conclusion, Italian ryegrass, Hwasan 101 was medium and late maturingvariety but excellent in cold-tolerance, lodging-tolerance, leafiness, and forage production.(Key words : Italian ryegrass, Cold tolerance, New variety)ian ryegrass, Cold tolerance, New variety)

• 원예과학기술지
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• 제32권5호
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• pp.607-613
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• 2014

Calcium has been associated with improved cold tolerance in many crops. The aim of this study was to investigate the changes in leaf cell $Ca^{2+}$ distribution and cell organelle ultrastructure of loquat (Eriobotrya japonica Lindl.) plants in response to cold stress at $-3^{\circ}C$, using transmission electron microscopy (TEM). Two loquat accessions, Zaozhong 6 (a commercial cultivar) and oakleaf loquat (a wild relative) were used. Cold tolerance, as measured by leaf browning rate, was higher in oakleaf plants, and calcium treatment improved cold tolerance in both species. Cold stress first induced inward transport of $Ca^{2+}$ from the intracellular space. Then, the imported $Ca^{2+}$ was aggregated around the chloroplast membrane, finally entering the chloroplast. This pattern of $Ca^{2+}$ distribution in leaf cells occurred earlier in Zaozhong 6 than in the wild loquat. With increasing time of cold exposure, the chloroplast membranes of Zaozhong 6 leaves were damaged, blurred and even disappeared, while those of wild oakleaf loquat leaves maintained their structure longer. In Zaozhong 6, cold stress induced a clear cavity between poorly structured granal thylakoids and vesicles appearing inside the chloroplast, while in oakleaf leaves cold stress had little effect on the ultrastructure of chloroplasts (although chloroplast membranes looked blurred). Loquat leaves accumulated free calcium ions around chloroplasts in response to cold stress, with earlier calcium accumulation occurring in the cold-sensitive cultivar Zaozhong 6 than in wild oakleaf loquat. These results demonstrate that these two loquat species have differences in both cold tolerance and calcium accumulation dynamics.

• 한국지역사회생활과학회지
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• 제18권4호
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• pp.599-607
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• 2007

We analyzed the effects of regular Jjimjilbang (Korean sauna) exposure on the cold tolerance in young and elderly females. Subjects were young (n=7) and elderly (n=7) females who had never had Jjimjilbang exposure experience. The Jjimjil training group was exposured in the Jjimjilbang 19 times per week. Jjimjibang exposure was limited to three times per day. Jjimjil activity was taken freely. To prove the effects of the cold tolerance, subjects were exposed to cold air ($12{\pm}1^{\circ}C,\;60{\pm}10%$RH). In these conditions, subjects were exposed for 30 minutes at which time rectal temperature, skin temperatures, clothing microclimate, energy expenditure, blood pressure and subjective sensation were measured. To prove the effects of the local cold tolerance, vascular hunting reaction was observed measuring the finger skin temperature while the left middle finger tip was immersed in cold water of $0^{\circ}C$ for 30 minutes. The results are as follows. According to repeated Jjimjil exposure, rectal temperature changes, peripheral temperature and energy expenditure were increased gradually in the cold climate chamber. Blood pressure, subjective sensation and vascular hunting reactions did not show any significant difference. In conclusion, regular Jjimjilbang exposure has negative effects on the ability of the body to improve its regulation of temperature especially in cold tolerance.

• ALGAE
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• 제25권2호
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• pp.99-104
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• 2010

A psychrotolerant cyanobacterium, Nodularia spumigena KNUA005, was isolated from a cyanobacterial bloom sample collected near Dasan Station in Ny-${\AA}lesund$, Svalbard Islands during the Arctic summer season. To generate an axenic culture, the isolate was subjected to three purification steps: centrifugation, antibiotic treatment and streaking. The broad antibacterial spectrum of imipenem killed a wide range of heterotrophic bacteria, while the cyanobacterium was capable of enduring both antibiotics, the remaining contaminants that survived after treatment with imipenem were eliminated by the application of an aminoglycoside antibiotic, kanamycin. Physical separation by centrifugation and streaking techniques also aided axenic culture production. According to the cold-tolerance test, this mat-forming cyanobacterium was able to proliferate at low temperatures ranging between 15 and $20^{\circ}C$ which indicates the presence of cold-tolerance related genes in N. spumigena KNUA005. This suggests the possibility of incorporating cold-resistance genes into indigenous cyanobacterial strains for the consistent production of algae-based biofuel during the low-temperature seasons. Therefore, it is needed to determine the cold-tolerance mechanisms in the Arctic cyanobacterium in the next research stage.

• 한국작물학회지
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• 제36권5호
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• pp.429-444
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• 1991

수도품종의 내냉성 관련인자로서, 생체막 구성물질로서 중요한 역활을하는 phospholipid의 지방산조성과 지방산 불포화비율, 생체의 가장 중요한 대사과정의 하나인 호흡에 관련된 특성인 mitochondria의 호흡활성, 광합성된 엽록소 형광강도 등 여러가지 생리적 인자들과 내냉성과의 관계를 검토하고 내냉성 품종선발과 냉해를 경감시킬 수 있는 방법을 모색하고자 관련자료를 종합정리하였다. 1. 지방산의 불포화비율은 저온처리를 함으로서 높아지는 경향을 보였으며, 내냉성정도와 비교하여 볼 때 내냉성이 강한 품종에서 불포화비율이 높고 약한 품종에서 낮아 내냉성 정도와 일치하는 경향이었다. 2. 경화처리에 의하여 인지질의 지방산조성중 palmitic acid는 감소하고 linolenic acid의 함량은 증가되었으며 지방산 불포화비율이 대조구에 비하여 19～24% 증가되어 내냉성을 증가시킨 것으로 생각되었다. 3. 수도 백화묘($25^{\circ}C$ 암상태 2주간 생육) 및 야외에서 생육시킨 유묘에서 분리한 mitochondria의 호흡활성 전이온도와 내냉성 정도와의 관계를 보면 내냉성이 강한 품종에서 전이온도가 낮았고, 약한 품종에서는 높은 경향이었다. 4. 생육시기별 mitochondria의 호흡활성 전이온도는 상풍벼 11.5～12.5$^{\circ}C$, 풍산벼 15.0～l6.$0^{\circ}C$, 샛별벼 17.0～l8.$0^{\circ}C$로서 큰 차이가 없었으나 내냉성 강, 중, 약 정도간에는 뚜렷한 차이를 보였다. 5. 엽록소 형광강도와 내냉성 정도와의 관계는 내냉성이 강한 품종에서 형광강도가 높고 약한 품종에서 낮은 경향을 보였으며 높은 산관관계를 보였다. 6. Mn을 엽면시용하므로서 호흡활성 전이온도를 0～2$^{\circ}C$ 낮추었으며 토양처리를 하였을 때 내냉성이 약한 품종에서 효과가 켰다 7 내냉성 정도와 인지질 지방산불포화도, 호흡활성 전이온도 및 엽록소 형광과의 관계에서 대체적으로 이들 세 인자와는 높은 상관을 보였으나 그중에는 독특한 반응을 보인 품종들도 있었으며, 호흡활성 전이온도는 지방용 불포화비율과는 부의 관계를, 엽록소형광과 지방산 불포화비율과는 정의 상관관계를 보였다.

• 한국지역사회생활과학회지
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• 제17권2호
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• pp.49-60
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• 2006

It was measured the energy expenditure in each season, the cold tolerance in winter and the heat tolerance in summer. Farmers' adaptability to the change of environment was compared with those of city-dwellers such as indoor workers and street cleaners to determine the effect of living environment, especially living temperature, on the health of human body. It turned out that farmers had experienced wide range of temperature that was higher in summer and lower in winter than indoor workers. Farmers and street cleaners showed seasonal adaptation in energy expenditure, which was high in winter and low in summer. However, indoor workers did not show seasonal changes. Energy expenditure had an inverse correlation with the temperature in work place where subjects spend the longer time in a day except in female indoor workers in Seoul. And It was proved that farmers and street cleaners had stronger cold tolerance and heat tolerance than indoor workers.

• 한국의류학회지
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• 제42권3호
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• pp.530-543
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• 2018

This study investigated elderly winter wearing habits and self-identified thermal tolerance in order to compare differences between older males and older females. We surveyed 269 participants: 119 males (age $76.9{\pm}5.9yr$) and 150 females (age $76.1{\pm}5.7yr$). Thirty one questionnaires were used: Self-identified cold and heat tolerance, clothing behavior, lifestyles related to the cold and health care, etc. High percentage of respondents (both males and females) felt vulnerable to the cold. The total number of outdoor clothes were $9.6{\pm}1.6$ and $10.6{\pm}1.6$ in males and females, respectively (p<.05). Wearing frequencies for thermal underwear were 84.0% and 82.4% in males and females, respectively. The using percentage of auxiliary heating devices was higher in females compared to males (p<.01). Males felt more cold in the head and face compared to females (p<.01). Self-identified cold tolerance had negative relationships with the total number of winter outdoor clothes for both males (r=-0.260) and females (r=-0.222) (p<.01). The perceived old age for both males and females was 72.4 yr. Sex differences should be considered when developing guidelines for winter clothing behavior for the elderly and educating them on how to improve health and cold tolerance.