• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1997.11a
• /
• pp.14-19
• /
• 1997

식물의 광반응은 광질과 광강도에 따라 상이하며, 광은 열을 동반하게 되므로 광만을 분리하여 생각할 수 없다. 즉, 광은 식물체의 체온과 엽온을 높이고, 잎의 수증기 장력을 증가시켜 증산을 촉진하므로 기화열을 발생하는 원동력이 되기도 한다. 따라서 광은 잎속의 수분이나 기공개도 등에 영향을 주기 때문에 광합성속도에 간접적인 영향을 미치기도 한다. (중략)

• Journal of Bio-Environment Control
• /
• v.29 no.3
• /
• pp.306-312
• /
• 2020

This study was conducted to investigate cucumber plants response to greenhouse environments by solar shading in greenhouse in the summer. In order to estimate heat stress reduction of cucumber plants by solar shading in greenhouse, we measured and analyzed physiological conditions of cucumber plants, such as leaf temperature, leaf-air temperature, rubisco maximum carboxylation rate, maximum electron transport rate, thermal breakdown, light leaf respiration, etc. Shading levels were 90% mobile shading of full sunlight, 40% mobile shading of full sunlight and no shading(full sunlight). The 90% shading screen was operated when the external solar radiation is greater than 650 W·m^-2. Air temperature, solar radiation, leaf temperature, leaf-air temperature and light leaf respiration in the 90% shading of full sunlight was lower than those of 40% shading and no shading. Rubisco maximum carboxylation rate, arrhenius function value and light leaf respiration of the 90% shading were significantly lower than those of 40% shading and no shading. The thermal breakdown, high temperature inhibition, of 90% shading was significantly higher than that of 40% shading and no shading. Therefore, these results suggest that 90% mobile shading made a less stressful growth environment for cucumber crops.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2003.02a
• /
• pp.412-417
• /
• 2003

작물의 생장상태를 측정하고자 기존의 연구자들에 의해서 많은 연구가 수행되고 있다. 그러나 작물의 생장을 감시하기 위한 기존의 방법은 파괴적이며 지속적이지 못하다는 단점을 지니고 있다. 작물이 생장 장해를 받아 눈에 띄게 작물의 생장변화가 보일 경우 작물은 이미 영구적인 손상을 받게 진다. 따라서 이런 작물의 생장 장해를 조기에 진단하여 작물의 생장 장해에 능동적으로 반응할 수 있는 방법의 개발이 절실히 요구된다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1997.11a
• /
• pp.61-65
• /
• 1997

본 연구에서는 반사필름 멀칭과 북측면의 반사판설치에 의한 보광이 토마토의 광이용에 미치는 영향을 밝히기 위해 토양 및 수경재배를 통해 토마토의 엽온변화, 기공특성, 증산ㆍ광합성속도등의 변화들을 중심으로 검토하였다. 보광 처리에 의해 토마토엽의 기공밀도는 증가하였으나 기공의 크기와 면적은 차이가 없었다. (중략)

• Journal of Bio-Environment Control
• /
• v.6 no.4
• /
• pp.292-298
• /
• 1997

These studies were conducted to verify the effect of the supplementary lighting by reflective film mulching and its establishment in the north side of greenhouse on the utility of light at tomato by means of investigating changes of leaf temperatures, stomatal features, transpiration rates and photosynthetic rates. Stomatal density of leaves were high in the reflective film mulching but sizes of stomata were not different. As the osmotic potential in rooting zone was low, the stomatal resistance was high, transpiration rate was low, and leaf temperature was increased by 40.62$^{\circ}C$. And also in the block of reflective film mulching photosynthetic rates were decreased hut chlorophyll contents were not different. Especially, there is an effect of controlling greenhouse whiteflies by treatment of reflective film mulching. It is thought that the reason of high quality or increasing yield at several crops by supplementary lighting, such as reflective film mulching, would be caused by influences of absorption and distribution of nutrients through high transpiration rate and photosynthesis which resulted from increase of stomata.

• Journal of Bio-Environment Control
• /
• v.24 no.3
• /
• pp.243-251
• /
• 2015

This study aimed to determine the effects of root zone cooling using air duct on air temperature distribution and root zone and leaf temperatures of sweet pepper (Capsicum annum L. 'Veyron') grown on coir substrate hydroponic system in a greenhouse. When the air duct was laid at the passage adjacent the slab, the direction of air blowing was upstream at $45^{\circ}$. The cooling temperature was set at $20^{\circ}C$ for day and $18^{\circ}C$ for night. For cooing timing treatments, the cooling air was applied at all day (All-day), only night time (5 p.m. to 1 a.m.; Night), or no cooling (Control). The air temperature inside the greenhouse at a height of 40 and 80cm above the floor, and substrate and leaf temperatures, fruit characteristics, and fruit ratio were measured. Under the All-day treatment, the air temperature was decreased about $4.4{\sim}5.1^{\circ}C$ at the height of 40cm and $2.1{\sim}3.1^{\circ}C$ at the height of 80cm. Under the Night treatment, the air temperature was decreased about $3.4{\sim}3.8^{\circ}C$ at the height of 40cm and $2.2{\sim}2.7^{\circ}C$ at the height of 80cm. The daily average temperature in the substrate was in the order of the Control ($27.7^{\circ}C$) > Night ($24.1^{\circ}C$) > All-day ($22.8^{\circ}C$) treatment. Cooling the passage with either upstream blowing at $45^{\circ}$ or horizontal blowing at $180^{\circ}$ was effective in lowering the air temperature at a height of 50cm; however, no difference at a height of 100cm. Cooling the passage with perpendicular direction at $90^{\circ}$ was effective in lowering the air temperature at the height between 100 and 200cm above the floor; however, no effect on the temperature at the height of 50cm. A greater decrease in leaf temperature was found at 7 p.m. than that at 9. a.m. under both All-day and Night treatments. Fresh weight partitioning of fruit was in the order of the All-day (48.6%) > Night (45.6%) > Control (24.4%) treatment. A higher fruit production was observed under the All-day treatment, in which the accumulated average temperature was the lowest, and it may have been led to a higher proportion of photosynthate distributed to fruit than other treatments.

• Solar Energy
• /
• v.10 no.3
• /
• pp.27-34
• /
• 1990

The main objective of this study was to find the relationship between transpiration rate and environmental factors for crops in hydroponic culture within plastic greenhouse by using the computer model developed from the heat balance around leaves of a crop. A computer model was developed and verified through comparison with the experimental results for lettuce in hydroponic culture in a polyethylene film house. The model may be extensively used for the water management and thermal environment study of crops in protected culture, if the supplemented studies for some crops would be accomplished.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.43 no.6
• /
• pp.103-112
• /
• 2001

The development of infrared thermometry has led many researchers to use plant temperatures, and specifically the temperature of the crop canopy in the field, for estimating the water stress of a crop. The purpose of this study was to evaluate the role of leaf temperature in irrigation scheduling. An experiment was carried out in a greenhouse with chinese cabbage. Leaf temperature was measured with infrared thermometry and evapotranspiration of the crop was measured by lysimeters. Influence of the difference between leaf temperature and air temperature on crop evapotranspiration was evaluated under varying water stress condition. A further objective was to evaluate the effect of other climatic variables on the relationship between evapotranspiration and temperature difference between leaf and air. A statistical model for estimating evapotranspiration using the temperature difference, relative humidity. and radiation was developed and tested. Crop water stress index was calculated using vapour pressure deficit and the temperature difference. Relations between the crop water stress index and crop evapotranspiration was tested. The index was closely related with evapotranspiration.

• Journal of Plant Biology
• /
• v.17 no.3
• /
• pp.107-112
• /
• 1974

Leaf temperature is complicated with the microclimate and the dry matter production in a plant community. But a daily change of leaf temperature varying by the locality in plant body or plant community is not yet clear. To resolve such a question, following experiment was designed; Helianthus tuberosus L., Glycine max L., Zea mays L., Impomoea batatas Lam., and Cucurbita moschata var. toonas Makino were planted in the different sandy loam, $2m{\times}2m-quadrat$, which has a eastern, southern, western and northern edge. In each plot 17-25 plants were planted and the distances between individuals spaced uniformly. And leaf temperature were measured by MR3-C type thermistor from 14th May through 20th August. It is seems that the upper leaf is affected by solar radiation, the lower leaf by released heat from the earth and the middle leaf by the conditions of both zones. Measuring the temperature of a leaf that is on terminal, central, left and right margins and base part, temperature of control plant in a leaf was sloped during about two hours from noon. It is noticeable as a "noon sleeping" phenomenon.henomenon.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.02a
• /
• pp.198-203
• /
• 2002

활착이 이루어지는 동안 접목묘 결합 부위의 식물체 온도 변화에 미치는 광질효과를 구명 하고자 열화상측정 시스템을 사용하였다. 접목묘의 활착기간 동안 접목 부위의 온도는 줄기 부위에 비해서 낮게 나타났으며, 활착이 이루어지면서 접목부위와 줄기부위의 온도차가 감소하였다. 접목묘의 식물체 온도는 백색광, 청색광, 적색광 및 혼합광의 모든 처리에서 광질과 무관하게 명기에 내려가고 암기에 올라가는 현상이 반복적으로 나타났다. 일반적으로 광합성이 이루어지는 명기에 엽온과 같은 식물체 온도가 높게 나타나는 것과 비교할 때 상기의 결과는 정반대에 해당하는 바 이부분에 대한 상세한 검토가 필요할 것으로 판단된다.