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Volume 38, Issue 1
Displaying 1-18 of 18 articles from this issue
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(2) Difference of the Upper and the Lower Surfaces of Leaves in Stomatal Diffusion and CO2 Absorption RateBak KO1982 Volume 38 Issue 1 Pages 1-8
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe relationship was investigated between stomatal resistance and CO2 absorption rate under different light-qualities. The action spectrum of photosynthesis of leaves was discussed from the view point of CO2 diffusion resistance. CO2 absorption rate and stomatal resistance were measured at the upper and the lower surfaces of cabbage, cucumber and lettuce leaves under an irradiation of three different lights (blue-green, yellow-red and red) from either the upper or the lower surface side of the leaf.
Results were as follows:
(1) Stomatal resistance of lettuce-leaf was smaller at the surface receiving the light than that at the opposite surface in every light. The resistances of cabbage and cucumber-leaves were smaller at the lower surfaces than those at the upper surfaces regardless of the direction of irradiation. The stomatal resistance at the light-receiving-surface was the smallest under blue-green light in all plants. At the nonirradiated surface, the light quality caused some effect on stomatal resistances in lettuce but not in cabbage and cucumber.
(2) CO2 absorption rate was larger at the surface with a smaller stomatal resistance than that with a larger resistance for all plants. But, CO2 absorption at each surface was not always large under the light situation from which a smaller stomatal resistance was derived. At the lower surface the stomatal resistance did not so remarkably affect CO2 absorption rate. At the upper surface, the stomatal resistance was the limiting factor of CO2 absorption for cabbage and cucumber, but not for lettuce.
(3) The ratio of CO2 absorption rate at the upper surface to that at the lower surface varied with the light-quality and the irradiation direction for all plants. In the case of irradiation directed to the upper surface, the ratio for lettuce was the largest and those for cucumber and then cabbage followed in every light. It is considered that the differences in photosynthetic action among plants were caused by the differences in the distribution, the activity of stomata, and in the anatomical characteristics of leaves.
(4) The relative value of photosynthesis in blue region in the action spectrum of photosynthesis increased with increasing ratio of the upper surface to the lower one in CO2 absorption rate in the case of irradiation directed to the upper leaf surface. This phenomena was explained by the difference in the extinction coefficient for light within a leaf. The blue light has a large extinction coefficient within a leaf and is mostly absorbed near the surface layer. Therefore, higher the ratio, the higher photosynthetic activity occurred in blue region.View full abstractDownload PDF (1022K) -
Ikuo HORIGUCHI, Hiroshi SUGAYA, Hiroshi TANI1982 Volume 38 Issue 1 Pages 9-14
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDue to the rising cost of heating oils in recent years, the subject of heat conservation on a greenhouse has become more important. In this aspect, the plastic films used for reducing heat losses must have low transmittance property for longwave radiation, also need to have low emissivity. The properties of plastic films which affect on the transfer of energy are important.
The paper discusses the measurements of reflectance, transmittance, and emissivity of longwave radiation (thermal radiation) upon various plastic films used for crop protection in agriculture, particularly in a greenhouse.
New measuring methods for reflectance and emissivity were presented, and the previous transmittance calculations (Hagiwara and Horiguchi, 1972) were improved by using newly obtained reflectance values. The transmittance values obtained from the present study are about 2-5 percent larger than the values obtained from the previous study. The reason for the discrepancy may be due to the negligence of the reflectance term in the previous calculation.View full abstractDownload PDF (2921K) -
The Heat Insulation Efficiency of Greenhouses and their Covering Materials (1)Hideo MINAGAWA, Kazuo TACHIBANA1982 Volume 38 Issue 1 Pages 15-22
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSOverall heat transfer of polyethylene film (PE) and polyvinyl chloride film (PVC) were measured in the experimental greenhouses with hot-air heaters on the clear and on the cloudy nights during the period Nov. 1979 to Jan. 1980. Both films are 0.1mm thick and have different physical properties for long-wave radiation. The heat insulation efficiency of the greenhouses covered with PE and PVC single layer was investigated, and the ratio of floor area to covering area for the experimental greenhouses, which is one of the indices for the heat insulation efficiency of greenhouses, was also taken into consideration. The results are as follows:
1. Using the ratio of the overall heat transfer and the overall heat transfer coefficients for the heat insulation efficiency, the PE-house revealed to be less efficient than the PVC-house. This can be due to PE being more transparent to long-wave radiation than PVC. The advantage in the PVC-house, however, decreased with the increasing of the inside-outside air temperature difference (Figs. 3 and 5).
2. The overall heat transfer coefficients of both greenhouses depended on the inside-outside temperature difference. As the temperature difference increased, the overall heat transfer coefficients decreased (Fig. 5).
3. The overall heat transfer coefficients of both greenhouses were smaller on the cloudy nights than that on the clear nights. When the condensation occurred at the interior film surface, the heat insulation efficiency of both greenhouses was increased, resulting in the decrease of the coefficient. The efficiency of the PE-house was more affected than the PVC-house when the condensation occurred (Figs. 6 and 7).
4. When the inside-outside air temperature difference was small, convective heat transferred from the outside air to the outside cover surface. With an increase in the inside-outside air temperature difference, convective heat flow occurred from the outside cover surface to the outside air. This phenomenon was observed more clearly in the PVC-house, and more on the clear nights (Fig. 4).
5. The ratio of floor area to covering area for the paticular type, such as those experimental greenhouses and trench houses, should be expressed as two different functions: One is the ratio for radiative heat transfer; the view factor of the covering area to the floor area and the wall area, the other is the ratio for convective heat transfer; (the floor area+the wall area)/the covering area.View full abstractDownload PDF (934K) -
Part 1. Relationship between the Freezing Temperature and the Frost Injury of Soybean SeedlingSyoichiro YAMANAKA, Juro HANYU, Tsukasa NISHIYAMA, Keiichi NAKAYAMA1982 Volume 38 Issue 1 Pages 23-28
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSMost experiments on the frost injury have adopted the method of cooling air and freezing plants in their experimental chambers. In order to conduct the study on the frost injury, we used the radiative cooling apparatus designed by Hanyu et al. (1978). In this apparatus plants were cooled by long wave radiation and were lead to death, because the plants froze resulting in sublimating on their surfaces.
Four kinds of experiments were conducted 40 times, respectively (Table 1). The mean courses of air- and leaf-temperatures in four experiments were shown in Fig. 2. Further, their mean values and their variations were shown in Table 2 and the histogram of the injury in each experiment was shown in Fig. 3.
In the case of natural freezing, the freezing temperature in soybean seedlings was about -5°C and the range of their variations was narrow as shown in Table 2 (Exps.1-3). Therefore, ice inoculation was carried out in order to extend the width of freezing temperature and as a result, the mean freezing temperature rose up to -3.9°C. The effects of the cooling and melting rates of plant to the frost injury were not clear in our experiments. The ratio of frost injury was denoted as the ratio of browning parts area to the leaf area.
It was recognized that the freezing temperature, T1, of extracellular solution and the minimum temperature, T3, after T1 were correlated well with the ratio of frost injury, I, as shown in Table 4. Further, the multiple correlation analysis with these factors gave the following equation:
I=-10.23T1-22.04 T3-54.60 and the multiple correlation coefficient of 0.748 was significant.View full abstractDownload PDF (779K) -
Makio HAYASHI, Toyoki KOZAI1982 Volume 38 Issue 1 Pages 29-36
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe value of daily heating degree hour (described as DH hereafter) is essential for calculating the heating load of a greenhouse during the winter months. Many researchers have so far proposed different equations for estimating DH values.
Equations for estimating DH have been investigated. DH (Unit, °C·h·day-1) in this paper is defined as the sum of difference in hourly temperature between inside setpoint and outside, only when the former is higher than the latter.
Firstly, comparisons of actual and calculated DH values were made to know the estimation error of each equation proposed so far. Actual DH values were obtained for the inside setpoint temperatures of 5, 8, 12, 16, and 20°C, using the hourly measured outside temperatures from the beginning of December in 1979 to the end of February in 1980 at 9 different locations in Japan.
Among the various equations, the one developed theoretically by Mihara (1978) was the best fitting for actual DH values. Mihara's equation requires the parameter values of setpoint, daily minimum, daily maximum, and daily average temperatures for estimation.
Secondly, the authors, on one hand, simplified Mihara's equation by expressing the daily average temperature as a function of daily minimum and maximum temperatures; on the other hand, they generalized his equation for estimating not only 24-hour DH values but also nighttime DH values. Nighttime DH value is necessary for the calculation of nighttime heating load (in the case that heating is not necessary during the daytime).
Furthermore, a new DH diagram was proposed (Fig. 4). Using the diagram, daily and nighttime DH values can be obtained easily for any setpoint, daily minimum, and daily maximum temperatures.
Finally, DH value for varying setpoint temperature was considered theoretically to a certain extent, and the usefulness of the DH diagram for varying setpoint temperatures was also shown.View full abstractDownload PDF (3125K) -
(I) The Effects of Wind Speed and Soil Moisture on Temperature Profile and Heat Balance at Night in WinterShigeto KAWASHIMA, Toshisuke MARUYAMA, Toru MITSUNO1982 Volume 38 Issue 1 Pages 37-44
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe atmospheric environment of a certain region is generated with many external and internal factors intertwined in complexity. Solar radiation, precipitation and atmospheric movement on a large scale are examples of external ones, and topography, vegetation, soil and water are examples of internal ones. The factors which we can control are the internal ones, but the wind, the factor which seems to be external at a glance can be changed to some degree with the use of a fan or the reforms of topography and vegetation.
In this paper, we discuss how much we can control the atmospheric environment near the ground, especially the thermal environment related to plant growth. For simplification here, we treat one-dimensional situation, i.e., heat balance structure with a flat surface. Moreover, we treat it at night in winter for two reasons. One is in such a situation of stable condition, then the effects of soil for the atmosphere may be clear. And the other is in such a situation we can discuss in relation to practical problem like a frost damage.
A group of equations that represents atmospheric-soil heat balance was constructed. The model based on this equation system was made. After the model had been ascertained with observed data, we simulated under some different conditions, then we could get realistic results. With these results the effects of wind speed and soil moisture to the thermal environment and to the heat balance structure were examined.
The effect of soil moisture (thermal property of soil) on air temperature reaches to a fairly high level as the wind becomes weak to a certain degree (Fig. 5).
The influence of wind speed on soil temperature exists for a dry soil slightly, but almost vanishes as the soil becomes wet (Fig. 6).
The effect of soil moisture on heat balance near the ground is clearer as the wind becomes strong (Fig. 7).
The influence of wind speed on heat balance near the ground exists on dry soil slightly.View full abstractDownload PDF (915K) -
Toyoki KOZAI, Tadashi ITO, Mitsuo INAYAMA, Hajime KOBAYASHI1982 Volume 38 Issue 1 Pages 45-50
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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Tatsutaro KONKO, Kiyotsune SHIRAI1982 Volume 38 Issue 1 Pages 51-54
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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A Preliminary ReportYukio OMOTO, Tsutomu UEWADA1982 Volume 38 Issue 1 Pages 55-58
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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Satoshi IWAKIRI1982 Volume 38 Issue 1 Pages 59-64
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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ASAE Engineering Practice: ASAE EP406Tadashi TAKAKURA1982 Volume 38 Issue 1 Pages 65-70
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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Takayuki Saito1982 Volume 38 Issue 1 Pages 71-72
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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Makoto Kiyota1982 Volume 38 Issue 1 Pages 73-75
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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1982 Volume 38 Issue 1 Pages 76-76,83
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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Taichi MAKI1982 Volume 38 Issue 1 Pages 77-82
Published: June 10, 1982
Released on J-STAGE: February 25, 2010
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1982 Volume 38 Issue 1 Pages 109a
Published: 1982
Released on J-STAGE: February 25, 2010
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1982 Volume 38 Issue 1 Pages 109c
Published: 1982
Released on J-STAGE: February 25, 2010
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1982 Volume 38 Issue 1 Pages 109b
Published: 1982
Released on J-STAGE: February 25, 2010
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