• 한국연초학회지
• /
• 제17권1호
• /
• pp.15-19
• /
• 1995

This study was made of the effects from exposure to air temperature and amount of solar radiation during the wilting period on the sunburn of burley tobacco. Tobacco stalks were cult with one hour interval from 8:00 to 16:00, and were left on the field to expose to weather, and tobacco single leaf placed under 4 temperatures regimes in indoor. Sun-burn of the leaves was occurred when the leaves were exposed to temperature higher than 33$^{\circ}C$, and to solar radiation more than 800w/$m^2$ between 11:00-15:00 in a day during the curing season. The leaf temperature was increased until 52$^{\circ}C$ under the weather condition. The tobacco leaves were also burned without solar radiation when the leaves were exposed to high temperature until 5$0^{\circ}C$ of leaf temperature. Sun-bum was increased at upper leaves and at higher moisture content of leaf.

• 생물환경조절학회지
• /
• 제29권3호
• /
• pp.306-312
• /
• 2020

본 연구에서는 여름철 고온기 시설재배시 수시차광이 내부환경과 오이 생리적 반응에 미치는 영향을 검토하였다. 온실차광이 오이의 고온 스트레스 완화 정도를 추정하기 위하여 잎 온도, 엽기온차, 최대 카르복실화속도, 최대 전자전달 속도, 열파괴, 광호흡과 같은 오이의 생리적 반응을 측정 분석하였다. 오이 시설하우스의 차광율은 90% 수시차광, 40% 수시차광, 무차광 3수준의 실험 조건으로 하였다. 90% 수시차광은 외부 일사량이 650 W·m^-2일 때 차광되도록 하였다. 기온, 일사량, 엽온, 엽기온차, 광호흡은 90%의 수시차광에서 40% 수시차광과 무차광 처리 보다 낮은 값을 나타내었다. 최대 카르복실화속도, 광호흡율은 90% 수시차광 온실이 다른 처리구보다 유의하게 낮은 것으로 나타났다. 고온저항성을 나타내는 thermal breakdown 값은 90%의 수시차광에서 다른 처리구 보다 유의하게 높은 것으로 나타났다. 따라서, 90% 수시차광이 여름철 오이 재배에 있어 고온스트레스를 덜받는 생육환경을 조성하였다는 결과를 얻었다.

• 한국연초학회지
• /
• 제18권1호
• /
• pp.66-75
• /
• 1996

This study was carried out to investigate the effects of high temperature and humidity on the ageing of processed leaf tobacco. Four(1993) or six(1994) grades (Both flued-cured and burley) of processed leaf packed in carton box were stored under the natural and artificial conditions. When the Processed leaf was stored in the controlled mom at 40℃ with 75% R.H.(1993) for 40 days, the leaf pH was decreased. The decreasing rate of leaf pH was similar to that of leaf stored under the natural warehouse condition for 15 months. The degree of lightness and yellowness of leaf also decreased, while the decaying or darkening of the leaf was observed. When the processed leaf was stored in the controlled room at 35℃ with 65% R.H.(1994) for 90 days, the pH of flue-cured was decreased 0.22, which was similar to that of the leaf stored under the natural warehouse condition for 15 months, and the lightness, and redness of the leaf were higher than those of the control. As compared with the leaf stored under the natural condition for 2 years, the smoking quality of leaf stored under this condition was similar or somewhat better. The pH of burley tobacco changed little compared to that of flue-cured during storage in this study.

• 한국의류학회지
• /
• 제38권4호
• /
• pp.540-556
• /
• 2014

This research investigated the effective conditions to dye cotton with commercial indigo leaf powder. We tested dyeing conditions of: pH of dyebath (6.5, 9-12), heating ($20^{\circ}C$, $50^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$), ageing (0, 0.5, 1, 4, 24 hours), reduction time (0, 30, 60 min), and dyeing temperature ($2^{\circ}C$, $10^{\circ}C$, $20^{\circ}C$, $50^{\circ}C$, $70^{\circ}C$, $80^{\circ}C$), dyeing was conducted for 20 minutes. The highest K/S value was obtained when cotton was dyed using pH 11 dyebath, heated at $50^{\circ}C$ for 30 minutes, aged for 24 hours at room temperature ($20^{\circ}C$), reduction carried out for 30 minutes, and dyed at $50^{\circ}C$. It is proposed that the K/S value is primarily influenced by the dyebath pH and dyeing temperature, followed by the presence or absence of ageing time and reduction time. The color of cotton with high K/S values was B type by Munsell hue value, which was similar to the color obtained in previous studies by freshly made indigo leaf powder and indigo leaf juice. The results indicate that the dyeing conditions established in this research are suitable to maximize the dyeability of commercial indigo leaf powder and that the indigo leaf powder can be used as a substitute for fresh indigo leaf juice.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2000년도 학술발표회 발표논문집
• /
• pp.151-156
• /
• 2000

This study was to evaluate the effect of leaf temperature on daily evapotranspiration of crop. A transpiring crop will be cooled by the vaporization of water to a temperature below that of the surrounding air. Leaf temperature was measured a infrared thermometer. Crop evapotranspiration was measured by the method of lysimeter. A statistical model for estimating evapotranspiration was developed and tested. It was showed that the model was applicable.

• Molecules and Cells
• /
• 제43권7호
• /
• pp.645-661
• /
• 2020

Leaf senescence is a developmental process by which a plant actively remobilizes nutrients from aged and photosynthetically inefficient leaves to young growing ones by disassembling organelles and degrading macromolecules. Senescence is accelerated by age and environmental stresses such as prolonged darkness. Phytochrome B (phyB) inhibits leaf senescence by inhibiting phytochrome-interacting factor 4 (PIF4) and PIF5 in prolonged darkness. However, it remains unknown whether phyB mediates the temperature signal that regulates leaf senescence. We found the light-activated form of phyB (Pfr) remains active at least four days after a transfer to darkness at 20℃ but is inactivated more rapidly at 28℃. This faster inactivation of Pfr further increases PIF4 protein levels at the higher ambient temperature. In addition, PIF4 mRNA levels rise faster after the transfer to darkness at high ambient temperature via a mechanism that depends on ELF3 but not phyB. Increased PIF4 protein then binds to the ORE1 promoter and activates its expression together with ABA and ethylene signaling, accelerating leaf senescence at high ambient temperature. Our results support a role for the phy-PIF signaling module in integrating not only light signaling but also temperature signaling in the regulation of leaf senescence.

• 생물환경조절학회지
• /
• 제6권4호
• /
• pp.270-276
• /
• 1997

잎상추의 품질 평가 기준을 도출하기 위하여 청치마 상추를 공시하여 수경재배하고 재배적 조건에 따른 상추의 품질변화를 조사한 결과는 다음과 같다. 수비액온도가 $25^{\circ}C$로 항온인 경우 일정할 경우 주상 생체중이 59.7g으로 수양은 가장 높았으나 외관품질점수는 5.2로 가장 낮았고 온도가 15$^{\circ}C$에서는 수량이 가장 났았으나 외관평유점수은 8.2로 가장 좋았다. 한편 수경액의 온도가 주야간 다를 경우 본 실험에서는 주야간이 각각 20/2$0^{\circ}C$일 경우와 25/2$0^{\circ}C$인 경우가 제일 높았고 그보다 고온이거나 저온일 경우 액양이 낮았는데 잎상추의 외관 품질은 주/야 20/15$^{\circ}C$(평균 17.5$^{\circ}C$)일 경우 제일 우수했고, 잎은 온도가 높을수록 진타익형으로 도장하였고, 외관품질이 현저히 떨어졌다. 하파재배시 60% 차광인 경우 생육이 10% 감소하였고 80% 차광에서는 25% 정도 수량이 감소하였으며 차광정도가 커질수록 엽록소 함량은 감소하고 초장, 근장은 길어지는 경향을 나타내었다.

• 한국기계가공학회지
• /
• 제5권1호
• /
• pp.19-26
• /
• 2006

The wear behavior as the hardness of the sliding elements on the dry wear has been investigated using a dual leaf-spring. The materials of the specimens are used as ten kinds along their hardness. In this study, both upper and lower specimens have been used the same materials. Using experimental data, we figured the relationship between wear coefficient and friction coefficient, and the relationship between wear coefficient and friction temperature. Also we combined friction temperature and friction coefficient instead of wear coefficient. We substituted this into wear equation of Archard. The result had been derived a newly wear equation in using dual leaf-spring wear system.

• 동아시아식생활학회지
• /
• 제7권1호
• /
• pp.57-63
• /
• 1997

In order to use leaf mustard Dolsan food preservative ingradient acidity, antimicrobial activity and colors were investigated during pretreatment of leaf mustard Dolsan. pH was remarkably decreased after 8 hours to pretreatment(extracted on shaking) of leaf mustard Dolsan, and no changes were observed after that time. pH of leaf part was higher than stalk after 8 hours storage. Titratable acidity was opposite tendency to the pH. pH was gradually decreased than initial stage during pretreatment of leaf mustard Dolsan at 30, 40 and 5$0^{\circ}C$. After 16 hours pretreatment, the higher pretreatment temperature was, the higher pH was, but after pretreatment for 48 hours, pH of sample pretreated at 5$0^{\circ}C$ was lower than that of sample pretreated at 40 $^{\circ}C$. Antimicrobial activity of leaf mustard Dolsan extract pretreated at 3$0^{\circ}C$ was the strongest of the samples pretreated at 30, 40 and 5$0^{\circ}C$, and that of stalk part was stronger than that of leaf part. L and time. L and b value was higher in the order of samples pretreated at 40, 50 and 3$0^{\circ}C$, and the lower pretreatment temperature was, the higher a value was. L value of stalk part was higher than that of leaf part, but a and b value of leaf part was higher than that of stalk part.

• ALGAE
• /
• 제19권1호
• /
• pp.39-47
• /
• 2004

Production dynamics of eelgrass, Zostera marina was examined in Jindong Bay on the south of the Korea peninsula. Eelgrass leaf productivities and environmental factors such as underwater photon flux density, water temperature, and nutrient availabilities in the water column and sediments were monitored from March 2002 to December 2003. While water temperature exhibited a distinct seasonal trend, underwater irradiance and nutrient availabilities exhibited high degree of fluctuation, and did not show a seasonal trend throughout the experimental periods. Eelgrass leaf elongation and production rates showed significant seasonal variations. Leaf productivity was highest in May (30.0 mg dry wt sht$^{-1}$ d$^{-1}$ or 3.7g dry wt m$^{-2}$d$^{-1}$) and lowest in November (3.2 mg dry wt sht$^{-1}$ d$^{-1}$ or 0.12 g dry wt m $^{-2}$ d$^{-1}$). Eelgrass leaf productivities did not show a strong correlation with underwater irradiance or environmental nutrient availabilities. The production rates, however, were positively correlated with water temperature during spring periods, and were correlated negatively at high water temperature exceeded 20℃ during summer months. While relative growth rates were highest in spring and lowest in high water temperature periods, plastochrone interval was longest during summer and shortest during spring. These results imply that seasonal growth dynamics of eelgrass, Z. marina was mainly controlled by water temperature.