Rice plants were grown in rooms of the phytotron at the Hokkaido National Agricultural Experiment Station. Leaf temperatures of the plants were measured by an infra-red radiation thermometer at the booting stage.
Leaf temperatures were close to the air temperatures in rooms where the temperature was maintained at 24°C (natural light rooms) or 23°C (artificial light rooms) . While in rooms where the temperature was 12°C (natural and artificial light rooms), leaf temperatures were higher than the air temperatures. In natural light rooms, the differences were about 4°C on a clear day and about 2°C on a cloudy day. In artificial light rooms, the differences were about 0 to 2°C, depending on leaf height. Single leaves (or leaf parts) which received light vertically or at an angle of more than 45° showed 1 to 2°C higher temperatures than those of leaf groups.

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The effect of wavelength width of monochromatic light on the action spectrum of protochlorophyllide phototransformation to chlorophyllide a was examined in vivo. At the 650 nm region which has been known as the peak of action spectrum, irradiation with 2 nm half-wavelength width gave larger transformation value than that obtained with 10 nm irradiation. However, at 600 nm and 670 nm wavelength regions, very little transformation was observed.
Wavelength width is shown to be significantly important in the selection of irradiated monochromatic light in the determination of action spectrum.

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The hypocotyl elongation was regulated by the automatic program control of temperature with the use of a computer system.
The hypocotyl length was measured in time course under the constant temperatures of 10, 15, 20, 23, 25, 27 and 30°C, respectively, and the hypocotyl elongation curves at respective constant temperatures were formularized. On the basis of the equation of the relations between the temperature and hypocotyl elongation, the temperature required for the desired hypocotyl elongation, was computed by each of the two methods: In the first method, the temperature (T_i) corresponding to an equation curve which satisfies the desired hypocotyl length (y_i) at an optional time (x_i) was computed from the equations of the relations between time (x) and hypocotyl length (y) at respective constant temperatures (T) . In the second method, the temperature (T_i) corresponding to an equation curve which has the same inclination as that of the desired hypocotyl elongation line at an optional time (x_i) was computed from the equations of the relations between time (x) and hypocotyl length (y) at respective constant temperatures (T) . The computed temperature was exchanged into voltage value and led into the temperature controller of the growth cabinet to control the temperature on line in real time. Two of the desired values of the hypocotyl elongation were given as follows; 1) y=7.5.x+10 (0≤x≤4) and 2) y=5.04x+10 (0≤x<2), y=0.71x+18.66 (2≤x≤4) .
When the temperature was computed by the second method, the hypocotyl elongation conformed to the desired values. However, when the temperature is computed by the first method, the hypocotyl elongation could not coincide with the desired value. From these results, it could be estimated that the temperature should be computed on the basis of the elongation rate, and further, it is suggested that computation of environmental factors should be made on the basis of the growth rate for the regulation of the plant growth.

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The sodium and potasium concentrations in the mixed and parotid saliva which were taken from the steers exposed to the high environmental temperatures and humidities were determined to assume the extent of aldosterone secretion as a measure of the environmental stress.
1) Under the environmental conditions of 42°C in temperature and 80% in humidity, the Na: K ratios in both of mixed and parotid salivas were decreased, suggesting increased aldosterone secretion.
2) Under the environmental conditions of 36°C or 33°C in temperature and 80% in humidity, the Na: K ratios of mixed saliva both decreased. On the other hand, the Na: K ratios of parotid saliva were remained unchanged in both environmental conditions.
3) When the steers are exposed to such severe heat stress as this experimental conditions, the salivary Na: K ratio was affected not only by the increased aldosterone secretion, but also by the reduced parotid saliva secretion and other unknown factors, depending on the extent of the stress.

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