Experiments on the effect of ultraviolet radiation on the anthocyanin content of the fruit pericarp were carried out in order to elucidate the causes of the inhibition of fruit-coloring in common eggplant (Solanum melongena L, var, esculentum Nees) occurring in some cases of“plastic house”cultivation.
The content of anthocyanin was decreased by covering the plants or fruits using films having an extremely low transmittance in ultraviolet region, regardless of the kind of film material. This fact was recognized in cases when covering was made to the whole plant by means of “house” cultivation (Fig. 1, Tables 1 and 2) as well as when only the fruit itself was covered by an envelope (Fig. 2 and 3, Tables 3 and 4) .
There was no clear correlation between the light transmittance of covering material and the anthocyanin content in the pericarp (Fig. 2, Table 3) . A close correlation was, however, found between the ultraviolet transmittance of covering material and the anthocyanin content in the pericarp when polyvinyl chloride films were used for fruit-covering (Fig. 4) .
Supplemental irradiation of ultraviolet to the fruit promoted the anthocyanin formation in the pericarp (Table 5) .

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A simple theoretical equation was introduced to calculate the heat transmission and the heat loss coefficient for a multi layered film plastic house in winter. The results calculated by this equation from the temperature values measured at a cylindrical model for the plastic house showed that the temperature difference between inside and outside of the plastic house was affected not only by the quantity of heat applied to the house but also by the effective radiation from the ground. During high rate of effective radiation from the ground, it was interestingly recognized that the over-all heat transmission calculated was usually negative in appearance if the heating quantity was not so large, because the radiant heat dissipated at the film to the sky in such condition was conducted more from the outside air than from the inside air through the film in spite of the inside air temperature was kept higher than the outside air temperature by heating.
It was concluded that the rise of the inside air temperature at the multi film system was basically due to the simple mechanism in which the covering of the outtermost film acted as an artificial warm sky (about -2°C) in place of the natural cold sky (about -27°C), and the total thermal resistance becomes in general about twofold at the double layers and about fourfold at the triple layers.

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The purpose of this paper was to investigate the relation between the cross section, number of doors of plastic houses and the heating load. If the heat lost from the plastic house is expressed in term of the conductivity (e) and the radiation (r), the rate of heating quantity required is expressed approximately by
q=e+r≅ Reff∅FSaF (1+γ)
where, Reff is the effective radiation, γ is equal to e/r. This e/r raises linearly with the decreasing rate of heating quantity (q) from -1 at non-heating to nearly 0 at the usual heating range. Therefore, the heating load for the plastic house is mainly affected by the view factor (∅FS) .
Giving an example of the plastic houses having semi-circular and pentagonal cross section with various distance of spacing between and number of doors, the mean value of the view factor of the whole house (∅FS) has been calculated to show graphically that the heating load decreases as the spacing becomes smaller and the number of doors becomes larger.

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1. A grating spectroirradiater (biological spectrograph) was designed and assembled for use in monochromatic light irradiation experiments on relatively large biological specimens, i. e. higher plants, in a controlled environment.
2. A short-arc xenon lamp (6.5 kW) was used as the light source. The dispersing element was a plane diffraction grating with a ruled area of 154×206 mm (1, 200 lines/mm, blazed at 600 nm) . The usable wavelength region was extended from 350 nm to 800 nm. A monochromator of the MONK-GILLIESON Mount type was used to obtain monochromatic light flux at as high an energy level as possible. Maximum intensity of the flux was 20, 000 erg/cm²/sec.
When entrance and exit slit widths were set at 0.5 mm and 5 mm, respectively, the half bandwidth of monochromatic light was 0.95 nm at 398 nm and 2.4 nm at 791 nm.
3. To simultaneously irradiate each specimen with monochromatic light beams of the same intensity and the same spectral bandwidth, relationships between the entrance slit width and exit slit widths, and the distance between the exit slit and specimen were examined. Conditions for setting them at appropriate values were studied.
4. To make the intensity distribution of monochromatic light on the irradiation plane uniform, a dispersing mirror composed of small convex mirrors arranged on a concave surface was contrived.
5. Stray light in the monochromatic light as measured with a double beam spectroradiometer was less than 10^-5.
6. Air temperature and relative humidity in the laboratory were controlled in ranges of 15°C-30°C±1°C and at 65%±5%, respectively.

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There are several mutant strains of which are unable to elongate only the 2nd internode counted below from upper position of culm in rice plants.
These mutant strains, Murasakidaikoku, Daikoku No. 1 and Daikoku No.4 etc., are all the dwarf rice plants.
It was found that the length of abnormal 2nd internode was controlled by a single recessive gene from the results of normal elongation of the 2nd internode in F₁ plants and segregation ratio of F₂ generation.
By controlling photoperiod and temperature condition, elongation of the heritable abnormal internode was induced as that of the 2nd internode in normal rice plant.
That is, the abnormal 2nd internode elongated under 10 hr day length and at 30°C day and 27°C night temperature condition, on the other hand the internode did not elongate under 14 hr day length and at 25°C day and 18°C night temperature condition.
Low nitrogen level in culture solution brought about the elongation of the abnormal 2nd internode as compared with high nitrogen level.

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