In Citrus natsudaidai HAYATA cv. Kawanoamanatsudaidai, fruits in the shade of trees begin to color prior to ones in the sunshine, where the rind of sunny side of fruits exposed to sunlight is delayed intensively in coloring and retains green. There were some difference in chlorophyll content of the rind between the sunny side and the shady side of fruits. But, chlorophyll content of the rind of the sunny side, one of which was changed from the shady side at certain time of the experiment, decreased later than that of the shady side did. When immature green fruits were covered with cheese-cloths which reduced transmittance of light in various degrees, the area of the green surface of the rind was retained as much as the shade was intensive, whereas, measuring the rind temperature, the covered treatments that the green color was much preserved caused to raise the rind temperature.
Most effective period of the shading on coloring was for Oct. 7 to Nov. 17 in regard to the green area retained, but the shading at early November was most inhibitory. Carotenoid contents increased as the shading was delayed.
When harvested fruits were storaged at 33, 26, 20°C and room temperature, separately, 26°C was greatest effect on coloring but 33°C was very inhibitory. Preservation of green in the rind was exhibited by gibberellin treatment, but other plant growth regulators such as kinetin were not effective.

View full abstract

Rind temperature of the sunny and shady side of fruits in the sunshine and shade was measured at midday every day. The sunny side of fruits in the sunshine showed much higher than maximum air temperature, being more than 30°C till late November. Whereas, shady parts of every fruits and/or the sunny side of fruits in the sunshine in rainy or cloudy days were nearly equal to maximum air temperature. Average temperature of the sunny side of fruits in the sunshine all through period of the experiment was 5.6 and 8.5°C higher than that of the shady side and maximum air temperature, respectively. Calculating the linear regressions on the rind temperature and maximum air temperature, regression equation and regression coefficient of the sunny side of fruits in the sunshine in fine days was y =0.665x+ 19.02 and r=0.809. The other hand, that of the shady side of them was y=0.849x +7.31 and r=0.974. Difference of the temperature of both side expanded as air temperature became lower.
As surveyed the distribution and diurnal fluctuation of rind temperature on various positions of the fruits to draw the isothermal lines and the maintenance hour of high temperature, the position on the rind that the retention of green color was observed showed remarkable ascent of temperature and had kept high temperature relatively long term in the day time. Rind coloring of citrus fruits proceeds probably along the isothermal lines as the seasonal changes.
In regard to effects of rind temperature of fruits covered or not on coloring, this order was as follows; fruits shaded for Sept. 4 (the beginning of the experiment) to Nov. 17 > shaded for all period of the experiment > in the sunshine for all period > shaded for Nov. 17 to the end of the experiment. The most former passed between 27 and 19°C through all the period. Whereas, the most latter continued to keep high temperature such as more than 28°C till mid November, and after passing at 19°C in late November, furthermore, lowered rind temperature extremely to 11°C in December. Result of the fruit coloring effected by shading period was discussed related to the rind temperature.

View full abstract

The physiological responses and the changes of plasma glucocorticoids concentrations of steers under severe hot and humid conditions were studied. The six Holstein steers were exposed to the six enviromental conditions of temperature and humidity within the range of 33-42°C and 60-80% in relative humidity.
1) The rectal temperature raised above 42°C in all steer and the time required to reach that temperature level was shortened as the effective temperature increased.
2) After the exposure, the respiration rate was increased rapidly to the maximum level followed by gradual decrease.
3) The heart rate was increased remarkably during the course of the death, while the rectal temperature was always above 42°C. The heart rate tended to decrease just before the death.
4) Only the conditions in which the steers were forced to death induced the increase of the plasma glucocorticoids, while the survived steers exhibited no concentration change in plasma glucocorticoids.

View full abstract

In Drosophila uirilis, phototactic selections to both positive and negative directions were performed for 40 generations by using a classification maze. The figure of responses to both directional selections was asymmetrical. The realized heritabilities of these photo-positive and negative populations were calculated by the regression slopes for the first 20 generations and these values were fairly low.
Reverse and disruptive selections were initiated from generation 34 of both photopositive and photonegative populations, and mean photoscores tended slightly to the photonegative side. From the results, the polygene, manifesting negative phototaxis, seemed to be partially dominant over polygene, manifesting positive phototaxis, or the number of polygene, responsible for both phototaxis was assumed to be different.
As several morphological and physiological characters correlated with the effect of selection, body size (weight and length), fecundity (number of eggs per fly per day) and walking behavior to light of unselected, photonegative and photopositive populations were compared with one another.
Photopositive flies had smaller body and laid lower mean number of eggs per day than photonegative flies. On the other hand, photopositive flies showed fast response to right, but their sensitivity to the change of light environments was dull and their life time was presumed to be short. Photonegative flies were close to unselected flies on such morphological and physiological characters. The correlative effects of directional selections for phototactic behavior would be either linkage relationship between some polygenic systems or pleiotropic functions of some polygene.

View full abstract

Some instruments of control and measurement of artificial light for plants were made in an attempt to analyze precisely the plant responses to the light.
Measurement of total and spectral irradiances. Two different instruments were used for measurement of light. One kind was a radiometer by which total irradiance in the wavelength range between about 300 nm and 800 nm was measured. The other was a spectroradiometer which was a newly assembled instrument, consisting of an integrating sphere (light receiver), a grating monochrometer, a photomultiplier, an amplifier, and a recorder. This spectroradiometer was able to measure spectral irradiance in the wavelength range between 300 nm and 800 nm, and in the irradiation range between 0.5 μW/cm²⋅nm and 500μW/cm²⋅nm with high resolution and reliable cosine response.
Light control. Six different lamps were used as light sources. They gave specific spectral emissions in the wavelength range between 350 nm and 800 nm. The lamp compartment of the growth cabinet was provided with these lamps. To control the radiant flux (light output) of each lamp, independent controllers corresponding to each lamp were used; the radiant flux control was achieved by SCR element for changing the effective current through the lamp. Both combined spectral and total irradiances were due to the radiant flux of each lamp. This instrument was able to control the total and spectral irradiances by changing the radiant flux of each lamp in the wave-length range between 350 nm and 800 nm and in the range between 0% and 100% of rated capacity.

View full abstract