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Volume 19, Issue 1
Displaying 1-9 of 9 articles from this issue
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O. TAKECHI, T. HASEBA, I. TOMARI1963 Volume 19 Issue 1 Pages 1-6
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSA micro-meteorological observation in a citrus orchard was carried out to clarify the effect of wrapping the crown of citrus trees in straw mats upon the cold wind prevention. Such wrapping method is usually employed for the protection against cold wind injuries to citrus trees.
The temperatures of leaf and the surrounding air were continuously measured for two months together with humidity, wind volocity, solar radiation, soil temperature and moisture content in or under the wrapping and unwrapping crowns.
The results are as follows;
1) The mean value of wind speed in the wrapped crown is about one-third of the open wind in speed range from 1.8 to 6.0m/s. The ratio of the wind speed in the crown to the open increases with the open wind speed, as shown in Fig. 1.
Such wind retardation is usefull to prevent the hastening of transpiration compelled by strong wind.
2) The nocturnal temperature of a leaf in the shade of straw mats is almost equal to the surrounding air temperature and higher than that of exposed leaf at a calm clear night, as shown in Fig. 2 (B) and Fig. 3 (A).
It is considerd that wrapping straw mats round the crown is not only important to retard the wind velocity in the crown, but also reduce the radiation outgoing from the leaf surface.
3) The temperature of soil under the wrapped crown goes down behind that of the bare ground when the air temperature falling.
On the contrary, the former goes up behind the latter when the temperature rising.
The air temperature, relative humidity and soil moisture are scarcelly affected by the wrapping.
At early spring, after this measurement, the citrus tree whose crown had been wrapped in straw mats showed better rate of the shoot growth than the unwrapped tree.View full abstractDownload PDF (893K) -
On the Heat Transfer from the Leaf of Citrus in Turbulent FlowO. TAKECHI, T. HASEBA1963 Volume 19 Issue 1 Pages 7-10
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe temperature of and the transpiration from citrus leaf were simultaneously measured in relation to solar radiation and wind velocity in turbulent flow parallel to the leaf surface.
Fig. 1 shows that the temperature departure of the leaf from air decreases with increasing wind velocity, when the difference between the solar radiation absorbed by the leaf and the transpiration heat is constant.
The heat flow from the leaf to air can be calculated as the residual term of the heat economy equation (14).
Fig. 3 shows the relation between logarithms of the heat transfer coefficient and of wind velocity.
Then, it is found that the former increases in perfectly linear proportion to the latter and the proportional constant calculated by least square method is 0.801±0.010.
This result coincides with the theoretical value of heat transfer coefficient on a flat plate in turbulent flow.
Therefore, the measured values of heat flow from the leaf coincide sufficiently with 1.35 times as much as the theoretical values of heat flow from a elliptical flat plate resembled to the leaf, as shown in Fig. 4.View full abstractDownload PDF (438K) -
K. YABUKI1963 Volume 19 Issue 1 Pages 11-14
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe various causes are considered of the midday depression of plant photosynthesis; the condition that the plants are grown under the extremely high temperature and the low carbon dioxide concentration of air in the plant community at midday is accepted as a cause of it.
The present paper discussed theoretically the midday depression of photosynthesis from the point of view of the diurnal variation of absorptivity of incoming radiation in the plant community.
Under the cloudy sky, that almost all of incoming radiation is the diffused light, the absorptivity of radiation of the plant community is nearly constant in a whole day, So, the total photosynthesis of foliages of a plant community will be proprtioned to the intensity of incoming radiation.
Under the sunny sky, that almost all of incoming radiation is the direct light and the path lengthes of the radiation within the plant community are varied with the solar angles, the absorptivity of radiation of the plant community changes diurnally and differs with the growth stages of plant Particularly at the middle stage of growth the absorptivity shows the remarkable diurnal variation which has the minimum. value at noon, Therefore the total photosynthesis of the foliages of the plant community decr eases around midday.
The conclusion seems to be quite reasonable in compared with Murata's data which observed the diurnal variation of photosynthesis through the various growth stages of paddy rice.View full abstractDownload PDF (535K) -
Diurnal Changes of Extinction Coefficient and PhotosynthesisS. KUROIWA, M. MONSI1963 Volume 19 Issue 1 Pages 15-21
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSRelative light intensities in thick foliage, which had generally been believed to be constant through-out the day, showed distinct diurnal change in white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) stands under cloudless conditions in summer at 40°30′S (Brougham 1958). This fact was theoretically elucidated in a previous paper. From Brougham's data, extinction coefficient (k) in the foliage has been approximately calculated with a formula, k=F-1ln (I0/I), where F, I0 and I indicate leaf area index, intensity of incident light and light intensity within foliage, respectively. The calculated k changes diurnally and reaches the highest in the white clover stand at a sun elevation of ca. 25°, and in the perennial ryegrass, of ca. 30°, at the said latitude. Such a saddle shape of diurnal k curves is most striking in summer, a little in autumn (or spring), and not recognized in winter.
Using the calculated k, hourly gross photosynthesis (Ph) of the pasture stands at latitude 40°30′ has been calculated by Saeki's formula, Ph=(b/ka) In [{(1-m)+kaI0}/{(1-m)+kaI0exp(-kF)}], where m is leaf transmissibility, and a and b are constants in the light-photosynthesis curve of a leaf. The foliage photosynthesis changes diurnally in larger F in parallel with increase of light intensity, but in smaller F it reaches a saturation value at early hour and decreased, though very slightly, by midday. This photosynthetic difference concerning the F values is remarkable in summer, but little in winter. Provided a diurnally constant value of k, the midday light-saturation of foliage photosynthesis occurs irrespective of F and season. These phenomena are explained with the relations of foliage photosynthesis to k and F.
Murata remarked with regard to midday photosynthetic depression a difference between early stage (or sparser stand) and later stage (oar denser stand) of paddy field. This difference can be better elucidated with analysis of the relationships between midday photosynthesis and k, and F. Our analysis of diurnal pattern of the foliage photosynthesis gives a criticism to Lemon and Musgrave's and Mihara's explanation as to foliage photosynthesis in a closed experimental system.View full abstractDownload PDF (1132K) -
1963 Volume 19 Issue 1 Pages 21
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
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M. KUSAKABE1963 Volume 19 Issue 1 Pages 22-24
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
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[in Japanese]1963 Volume 19 Issue 1 Pages 25-29
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
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[in Japanese]1963 Volume 19 Issue 1 Pages 30-31
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (405K) -
[in Japanese]1963 Volume 19 Issue 1 Pages 32-36
Published: August 15, 1963
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (895K)
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