Hybrid data-processing system of Fig. 12 was designed. This system is composed of Analog Computer (Fig.11), digital computer and linkage system. The linkage system is composed of operation control system, auto-scan control system and auto-setting control system. This system (unilateral hybrid system) is suitable for solution of partial differential equation in the environmental engineering and simulation of environmental control system.
High speed bilateral hybrid system with digital computer-interface is necessary thema for the next step.
This work was partially supported by the Grant-in-Aid from the Ministry of Education.

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The analysis of fluctuation of the air-flow in the Controlled Green-house was done.
Autocorrelation function (Cxx) and power spectrum dencity function (PSD) from time series of the air-flow were calculated by mini-digital computer.
From Figs. 15-18 and. Fig. 19, the relation betweeen plant-physiological characteristic and spectrum of fluctuation of the air-flow was made clear.

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To inquire the effect of physical factors on cell growth and differentiation in plant tissue culture, an estimation was performed on environmental conditions in which our experiments were proceeding using petri dishes, Erlenmeyer flasks and test tubes.
Besides on temperature conditions, characteristics in wavelength of monochromatic light produced by interference filters, prexiglass or colored-cellophane were measured spectro-radiometrically. Light intensity in petri dishes used was not essentially different from that at outside of dishes, but in Erlenmeyer flasks capped with aluminium foil, light energy reduced to 50 per cent in white light and below 3 per cent in monochromatic light at inside of the flasks. As illuminated monochromatic light obliquely, it was able to make the difference of light energy in and out of the flasks be a little.
A conspicuous difference was not found between internal and external temperature of test tubes in glass rooms under natural light. Concerning effects of temperature condition on growth of rice callus tissues, a difference was observed of sensitivities to low temperature in rice varieties. At 10°C more remarkable decline was obtained in callus growth of Tan-ginbozu variety than of Aichi-asahi.

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This experiment was performed in the phytotron of the Hokkaido National Agricultural Station to clarify the interrelationships between the distribution of air temperature or wind velocity and the characteristics of soybean plants grown in the natural light room.
Seventy two pots, each of which has two plants standing in an east-west direction, were arranged on the twelve trolleys in unf ormity.
Horizontal distribution of air temperature in the foliage zone of 70 cm height revealed that there was a thermal difference of 1.5°C between the wall side and the south side with a steady decline in temperature as the distance from the wall was farther. The wind velocity at a height of 70 cm ranged from 20 to 30 cm/sec at the most of measuring points, and it was found that there was negative correlation between wind velocity and stem elongation. Futhermore, it was shown that the distribution pattern of these two environmental factors under plant growing condition in 70 cm height was almost similar to those under an empty condition.
The stem length and the fresh weight of soybean plants increased as the plants were grown farther from the wall. Within the pot-trolleys, the average stem length of the inner row is steadily higher than those of the outer. A similar tendency was also observed in the fresh weight measured 57 days after planting. The number of days to flowering from sowing was delayed at the south side as compared with those of the plants at the wall side.
From these facts mentioned above, it is clear that increased stem length, fresh weight and delayed flowering time were due to low temperature and high wind velocity. Decreased stem length at the wall side resulted from the elevated temperature near the wall causing by the flux of sensible heat and by the reflection of light from the wall.
The coefficient of variation of the stem length was 8.1 per cent and was smaller than that of field grown plants and was greater than that of the plants grown in the glass house having no equipment for thermal controlling, as shown in Table 2. It is desirable to use any adequate methods in order to reduce coefficent variation, in the case of more accurate experiments required in the glass rooms of the phytotron.

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Composite sources of “Yuko lamps” reflected type, 400W (DR400/T) and blue fluorescent tubes, 40W (FL40B-F) were tested for simulating the spectral quality of real phases of daylight in the visible range, using a light panel and a growth cabinet (Fig. 1) .
It was proved that the spectral distribution curves of the composite light were assemble closely to those of daylight in corresponded color temperatures from 4, 500 to 7, 500°K (Fig. 4), and that the deviation in the relative band energy ratios of the composite light to daylight was within ± 15% in the wavelengths from 400 to 750 nm (Table 1) and there was no remarkable difference in the band ratios of B/R, R/FR, and B/FR between the composite light and daylight (Table 2) .
The distribution of illuminance and spectral quality of irradiance in the cabinet was examined under the composite source of 4 Yuko lamps and 14 blue fluorescent tubes. As the result, it was found that the horizontal distribution of illuminance was within ±15% at the distance longer than 50 cm from the lamps (Fig. 5) and the rates of spectral components and the energy ratios were little different in the horizontal and vertical positions (Table 3) .

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For studies on biotronics of fundamental problems in environmental control in biology, high accurate control of environmental factors was demanded. The growth cabinet is considered as an effective tool for such purpose. Present report deals with a trial to develop a growth cabinet with capacity of high accurate control, and following results were obtained.
1) It became possible to control temperature from -5°C to 40°C with accuracy of ± 0.5°C. The P. I. D. control action contributed to remove off-set and cyclic variation in temperature control. In the case of program control, temperature gradient of 10°C/30 min was obtained.
2) Relative humidity was controlled from 40% to 80%±3% at temperature range from 10°C to 40°C. In program control, falling and rising gradient of relative humidity was 10%/15 min.
3) Wind direction, velocity and distribution were kept uniform by 16 fans installed at the side of air supply compartment. Wind velocity ranged from 0.2 m/sec to 0.5 m/sec.
4) The canopy provided 45 fluorescent lamps of 40 W (FLR40S·W-SDL-AP/M) and 8 incandescent lamps of 100 W. At 50 cm above floor 20, 000 lux (110μW/mm²) of light intensity was obtained. However, it is not clear whether the spectrum distribution of the light is suitable for plant, or not.

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The activity of cytokinins has much bearing on the environmental factors, especially temperature condition, during growth. Some experiments were carried out to obtain clearer informations about this relationship. The growth promotive effect by a cytokinin, N-6-benzylaminopurine (BA), attained to the maximum at 20-27°C in every experiment, and lowered abruptly or was even suppressed than the untreated plants in some cases. But this temperature range was not fixed and was affected by the temperature environment preceding the experiment. When the temperature at germination or at growing before the experiment was low (5-16°C), the incubating temperature showing maximal cytokinin effect for fresh weight increase of detached radish cotyledons shifted to higher range (27-30°C), whereas no activity was observed or even the fresh weight increase was suppressed at 30°C when growing temperature was high (25-30°C), this activity lowering or suppression being augmented by high concentration of BA (100mg/l) . The BA effect seemed to be most prominent in temperature range for optimal growth of plant material as can be noticed from remarkably higher activity at 20-27°C than in lower incubating temperature (5-15°C) . Lastly, light condition, e.g., red light, seemed to augment the BA activity compared with dark condition, but further studies will be necessary concerning the relationn between temperature and light condition by setting up more strictly constant and uniform light condition.

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1. Examination of irradiated monochromatic light purity was attempted using protochlorophyllide phototransformation to chlorophyllide a and chorophyll a accumulation as the index. Examination was carried out in the region from 700 am to 800 nm. Monochromatic light was obtained from a Grating Spectroirradiater, Biological Spectrograph.
2. Twelve % of the phototransformation found by irradiation with 650 nm light was prefered as the most efficient light for phototransformation, at 10 erg/cm²/sec for 10 min. However, phototransformation was not detected by irradiation above 700 am light at 20, 000 erg/cm²/sec for 10 min. By simultaneous irradiation with 720 nm and 650 nm light, the same level of phototransformation, in comparison with the value of 650 nm alone, was observed. The extent of stray flux in light above 700 am at 20, 000 erg/cm2/sec might be considered at the level of intensity that has an equivalent relationship concerning phototransformation between stray flux and 650 nm light. Phototransformation is useful as the index of monochromatic light purity.3. By irradiation with monochromatic lights above 700 nm at 20, 000 erg/cm²/sec for 20 hours, a peak of chlorophyll accumulation was observed in the 720 nm region. From evidence that the induction period of accumulation by irradiation in this region is longer than that for 650 nm light and that the remaining photoconvertible protochlorophyllide was found in greening leaves, then chlorophyll accumulation in the 720 nm region might be due to unknown effects of 720 nm intense light. Chlorophyll accumulation in this region was unsuitable for use as an index in examining stray flux.
4. Using 780 nm light irradiation at 20, 000 erg/cm²/sec for 20 hours, 3μg/g F. W. of chlorophyll content was found. No chlorophyll was found in leaves irradiated by 790 nm and 800 nm lights. Therefore, chlorophyll accumulation in the 790-800 nm region was used as the index.

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