• Weed & Turfgrass Science
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• v.2 no.1
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• pp.47-54
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• 2013

The study was conducted to investigate early establishment characteristics and germination pattern of fine-textured fescues (FF) under natural room temperature and to analyze differences between alternative and natural conditions for a practical application. Six cultivars from Chewings fescue (CF), creeping red fescue (CRF), hard fescue (HF) and sheep fescue (SF) were evaluated in the study. Daily and cumulative germination pattern were measured and analyzed. Significant differences were greatly observed in germination pattern, days to the first germination, days to 60% germination, and germination percentage with environments, species and cultivars. Final germination rate was 29.7 to 80.0% under natural conditions. The first germination was initiated between 8 and 10 DAS (days after seeding) under natural conditions, being 3 to 4 days later as compared with ISTA conditions. Days to the 60% germination were 12.1 to 19.0 DAS, being 3.0 to 4.2 days slower than that under ISTA conditions. CF 'Jamestown II' was the fastest cultivar, while the slowest CRF 'Audubon'. Turf establishment speed was faster with CRF < SF < HF and < CF in order. Information on differences in germination characteristics and pattern between alternative and natural conditions would be practically useful for a golf course construction etc., when established with FF.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.274-282
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• 2013

Research was initiated to investigate early germination and establishment characteristics of perennial ryegrass (PR, Lolium perenne L.). An alternative condition was applied in Experiment I with 8-hr light at $25^{\circ}C$ and 16-hr dark at $15^{\circ}C$ (ISTA condition). Experiment II was conducted under $5^{\circ}C$ to $25^{\circ}C$ (natural condition). Significant differences were observed in germination percentage, germination speed and germination peak time. Seed germinating vigor was 66.00 to 93.75% under ISTA and 66.25 to 93.50% under natural conditions. Germination speed, measured as days to germination of 50% through 90%, was much faster with 'Pennant II', 'Brightstar II', 'Sonata' and 'Accent II' under ISTA conditions. But it was faster only with 'Pennant II' and 'Brightstar II' under natural conditions. Germination peak time ranged 1.48 to 5.65 days under ISTA, while 2.17 to 10.63 days under natural conditions. Regardless of growing conditions, the shortest cultivars in peak time were 'Sonata', 'Pennant II', and 'Brightstar II' and the longest one 'Revenge GLX'. Considering germinating vigor, early germination speed and germination peak time, 'Pennant II', 'Brightstar II', 'Sonata' and 'Accent II' were regarded as excellent cultivars under ISTA conditions, while 'Pennant II' and 'Brightstar II' under natural conditions.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.2
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• pp.39-47
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• 2018

This study was carried out to investigate the applicability of alternating temperature control during night time in a nursery seedling production. Three groups of samples were exposed to three different environmental conditions for 6 days from 18:00 to 09:00; one was constantly 15 ℃, another was alternating between 15 ℃ for 2 hours and 11 ℃ for 2 hours, and the other was alternating between 15 ℃ for 2 hours and 11 ℃ for 4 hours. Leaf temperature and stem temperature was measured in real time. The influence of cold stress was analyzed by flavonoid content and growth of tomato seedling. The temperature of leaves and stem became equal to the ambient temperature over time, furthermore, there was no significant difference among the treatments. In conclusion, it is considered that heating costs can be saved considerably, as the alternating temperature has fewer effects on cold stress reaction by tomato seedling growth.

• The Korean Journal of Soil Zoology
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• v.5 no.2
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• pp.119-123
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• 2000

Effect of fluctuating temperatures on the development of the immature beet armyworm, Spodoptera exigua (H bner), was analyzed. At constant rearing temperature regimes, the estimated developmental threshold temperatures were varied among stages and instars, but had an average 13$^{\circ}C$ from egg hatch to adult emergence. Based on the 13$^{\circ}C$ threshold temperature, we set up three different rearing temperature regimes having the same day-degrees. Two fluctuating temperature regimes changed significantly the developmenta1 period expected by the constant rearing temperature regime. Under the same thermophase temperature (25$^{\circ}C$), the thermocycling regime with the higher cryophase temperature (10$^{\circ}C$) decelerated the developmental rate probably by lowering temperature limit thor development, but that with the lower cryophase temperature (5$^{\circ}C$) gave a negative developmental effect.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.72-72
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• 2018

우리나라의 대형 저수지에 담수된 수체는 여름에 온도가 높은 표수층과 온도가 낮은 심수층, 그리고 두 층 사이에서 온도가 크게 변화되는 변온층으로 나뉘게 된다. 여름 홍수기에 상류 하천에서 저수지로 유입되는 부유사는 큰 밀도를 가지기 때문에 저수지의 바닥을 타고 하층 밀도류의 형태로 저수지 하류로 전파된다. 그러나 밀도류가 성층화된 저수지의 변온층에 도달하면 심수층과 변온층 하층의 낮은 온도로 인해 발생하는 수체의 큰 밀도로 하층으로 더 침투하지 못하고 변온층이나 심수층 상층에서 남아 하류에 중층밀도류의 형태로 전파된다. 대량의 탁수를 하류에 방류하면 하류 수질에 문제가 발생되며 저수시키면 댐 수질 및 심수층 생물체의 태양광 차단 문제가 발생되므로 저수지에서 밀도류의 조절은 대형 저수지 운영에 매우 중요한 사항이다. 따라서 본 연구의 목적은 층적분 모형을 사용하여 대형 저수지에서 발생하는 중층밀도류의 전파 및 선택취수시설을 이용한 밀도류의 차단과 방류에 대해 수치모의하는 것이다. 이를 위하여 중층 밀도류를 수치모의하기 위한 1차원 수치모형을 제시하였으며 소양강댐 상류 소양호에 적용하여 적용성을 검토하고 밀도류의 전파 및 방류에 대해 분석하였다.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.1-10
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• 2011

This study was conducted to investigate early germination characteristics and germination pattern of new cultivars of creeping bentgrass (CB, Agrostis pall/stris Huds.) under natural room temperature conditions and to analyze differences between alternative and natural conditions. Seven cultivars of CB were tested in the study. Daily and cumulative germination patterns were measured and analyzed on a daily basis. Significant differences were observed in germination pattern, days to the first germination, days to 50% germination, days to 85% germination, and germination rate among cultivars under different environments. The first germination in all entries was initiated between 4 and 5 days after seeding (DAS) under alternative conditions, while between 6 and 8 DAS under natural conditions, being 2 to 3 days later as compared with that of alternative conditions. As for the first germination percentage, it was generally 5 to 25% under alternative conditions. However, 'Penn A-1', 'Penncross', and 'Penn A-4' cultivars showed a vigorous germination, producing 50 to 70%. Under natural room temperature conditions, it was 5 to 10% for the most entries, except 'Penncross', 'L-93', and 'Penn A-4' cultivars which vigorously produced 20 to 50%. Days to the 50% germination in CB resulted in 4 to 10 DAS under alternative conditions, while 6 to 15 DAS under natural conditions, being 2 to 5 days later than under alternative conditions. Days to the 85% germination were 5.90 to 11.75 DAS under alternative conditions and 7.95 to 12.50 DAS under natural conditions. 'Penn A-1' and 'L-93' were the fastest cultivars under alternative and natural conditions, respectively. Regardless of the temperature conditions, the longest cultivar in germination was 'T-1', being over 11 DAS. In-depth comparative data on germination characteristics and germination patterns among CB cultivars would be usefully applied for a practical CB turf establishment in golf course construction etc.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1709-1714
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• 2004

The changes of microflora and enzyme activities in Alaska pollack sikhae were evaluated in 3 different temperature conditions, 5$^{\circ}C$, 2$0^{\circ}C$ and alternating temperature (stored at 5$^{\circ}C$ after 10 days of fermentation at 2$0^{\circ}C$), respectively. The number of proteolytic bacteria and 2 lactic acid bacteria including Lactobacillus sp. and Pediococcus sp. increased rapidly up to 10 days and composed major portion of total viable cell (TVC) in sikhae fermented at 2$0^{\circ}C$, whereas those of TVC were occupied by Lactobacillus sp., Pediococcus sp. and yeast after 10 days of fermentation. The major species of microflora in sikhae fermented at alternating temperature were, composed of Lactobacillus, Pediococcus and Streptococcus after 10 days of fermentation. Especially, Leuconostoc sp. was kept up to 27 days at 5$^{\circ}C$ than other temperature conditions (16 days). The activities of protease and lipase in acidic region (pH 3.0) were higher at 2$0^{\circ}C$ than at 5$^{\circ}C$ due to sensitivity of temperature, although those of protease and lipase in neutral region (pH 7.0) were not found any differences in both temperatures. Changing temperature condition from 2$0^{\circ}C$ to 5$^{\circ}C$ in alternating temperature inactivated protease activity, whereas lipase activity was still maintained during fermentation.

• The Korean Journal of Food And Nutrition
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• v.17 no.4
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• pp.405-411
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• 2004

The sensory properties in Alaska pollack sikhae were compared in 3 different temperature conditions, 5$^{\circ}C$, 20$^{\circ}C$ and alternating temperature(stored at 5$^{\circ}C$ after 10 days of fermentation at 20$^{\circ}C$), respectively, during fermentation. The change of instrumental texture including hardness, cohesiveness, adhesiveness and chewiness increased and/or decreased without significant difference in the sikhae fermented at 5$^{\circ}C$ during fermentation. Three profiles, hardness, chewiness and cohesiveness in the sikhae fermented at 20$^{\circ}C$ increased up to 12 day and then decreased, whereas those in alternating temperature decreased significantly. From the acceptance test during fermentation, sikhae products fermented for 14 days at 5$^{\circ}C$, 9 days at 20$^{\circ}C$ and 13 days at alternating temperature were superior in sensory properties. The score more over 5 point in overall acceptance was maintained until 14 days in 5$^{\circ}C$, 9 days in 20$^{\circ}C$ and 13 days in alternating temperature, respectively, and particularly, alternating temperature condition was superior to the different temperature conditions. The sensory texture and overall acceptance had the high positive correlation with chewiness and taste, respectively. From the result of quantitative descriptive analysis, the intensities of acidic odor and taste in alternating temperature maintained and/or increased during 27 days of fermentation, whereas those in sikhae fermented at 5$^{\circ}C$ decreased. These results demonstrated that cold chain system such as alternating temperature was needed for shelf-life extension and producing of marketable Allaska pollack sikhae.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.05a
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• pp.259-260
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• 2003

분포가 확대되어 가고 있는 미국자공의 서식지 환경요인과 발아특성을 조사하였다. 그 결과 광의 구배에 따른 기온의 차는 없었으나, 지온의 일교차는 상대조도에 따라 아주 다르게 나타났다. 실생 출현은 100%에서 150개체가 출현하였고, 33%에서는 80개체가 출현하였지만 8%에서는 출현하지 않았다. 2002년 채집되어진 종자는 광조건에 관계없이 항온에서 거의 발아하지 않았으나 광조건하의 변온에서는 발아율이 70%, 암조건하의 변온에서는 25%의 발아율이 보였다. 미국자리공의 발아는 광조건보다 지온변화에 보다 직접적으로 영향을 받는 것으로 판단된다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.24-24
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• 2023

본 실험은 한반도 극지 고산식물인 진퍼리꽃나무[Chamaedaphne calyculata (L.) Moench] 종자의 형태적 특성을 조사하고 변온조건과 저온처리 및 GA3 처리가 발아에 미치는 영향을 구명하고자 수행하였다. 진퍼리꽃나무 종자는 국립수목원 전시원에서 채종 후 4℃에 저온건조 저장하였으며 전자현미경(DVM6, Leica Microsystems GmbH, Wetzlar, Germany)을 이용하여 종자와 배의 길이를 측정하였다. 2022년 3월에 growth chamber 내에서 32일간 15/6℃, 25/15℃ 변온조건하에 배양하였으며, 저온층적처리(0, 40일) 및 GA3 처리(0/500/1,000mg·L^-1) 처리에 따른 발아 특성을 구명하였다. 진퍼리꽃나무 종자의 최종발아율(FGP)은 25/15℃ GA3 1000mg·L^-1 처리에서 42.2%로 가장 높게 조사되었다. 평균발아일수(MGT)는 15/6℃ 저온층적 처리에서 22.3일로 가장 높았으며, 대부분 15/6℃ 변온조건에서 25/15℃ 변온조건보다 6∼8일 높았다. 최종발아일의 평균은 약 12일로 확인되었다. 저온 층적처리 결과, 최종발아율(FGP)은 온도조건 25/15℃, 15/6℃에서 각각 32.2%와 11.1%를 보여 무처리구에서 조사된 24.4%와 10.0%보다 각각 7.8%, 1.1% 높게 나타났다. 호르몬처리 결과, 동일한 발아조건에서 GA3 500mg·L^-1 처리보다 1000mg·L^-1 처리에서 더 높은 발아율을 보였다. GA3 1000mg·L^-1 처리에서의 최종발아율(FGP)DKSH은 25/15℃, 15/6℃ 각각 42.2%와 30.0%를 보여 무처리구 보다 각각 17.8%, 20% 높게 나타났다.