Germination requirements were studied on the Bolivian pepper, ‘No. 3341’ (Capsicum chinense) seeds.
The soaked seeds did not germinate, when they were held at the constant temperature of 30°C. Inserting the temperature treatment of 15°C for 24 hr 7 days after the start of soaking the seeds, resulted in quick and high rate of germination. Temperature treatments of 25°C for 8 hr 7 days after, or of 15°C for 24 hr 1 day after the start of soaking the seeds, were also effective to some extent.
Illuminating the soaked seeds held at the constant temperature of 30°C, resulted in germination of nearly half the seeds. The ‘No. 3341’ seeds were thus recognized to be light germinators. Repeated alternations of temperature effected the seed germination in the dark.
GA₃ (gibberellic acid) treatment at 50 ppm was effective to promote the seed germination irrespective of illumination. GA₃treatments at concentrations other than 50 ppm, however, effected the seed germination only when accompanied by illumination. GA₃treatment at 100 or 250 ppm in the dark resulted in inhibition of the seed germination.

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The phenological characteristics and light dependence of the photosynthetic rate of Yachidamo ash (Fraxinus mandshurica var. japonica) were examined in view of the developmental difference between seedlings and saplings. The leaf-emergence duration and ‘leaf duration’ of seedlings were longer than those of saplings. The light compensation point at 20°C of photosynthesis was lower in seedlings than in saplings. The initial slope of the light-photosynthesis curve of seedlings was steeper than that of saplings. At higher light energy above 145 μE⋅m^-2⋅s^-1, the photosynthetic rate was higher in saplings than in seedlings. The light was saturated at 635 μE⋅m^-2⋅s^-1 with photosynthetic rate of 12.50 mgCO₂⋅dm^-2⋅hr^-1 for the former, and at 355 μE⋅m^-2⋅s^-1 with the rate of 6.18 mgCO₂⋅dm^-2⋅hr^-1 for the latter. Dark respiratory rate of a leaf was higher in saplings than in seedlings in the temperature range of 6°-30°C. The above mentioned results imply that the seedlings and saplings of Yachidamo ash seem to change their photosynthetic functions and phenological characteristics with its developmental stage under different habitat conditions.

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These experiments were carried out to clarify the effects of meteorological elements on daily growth of plant parts used as food of some vegetables growing in plastic house. Vegetables used are cucumber (Cucumis sativus L. cv. Buru-esu), tomato (Lycopersicon esculentum Mill. cv. Taibyo-shinhokan No.2), lettuce (Lactuca sativa L. (capitata group) cv. Great Lakes 366 and cv. Okayamasaradana), garland chrysanthemum (Chrysanthemum coronarium L. cv. Oba), spinach (Spinacia oleracea L. cv. King of Denmark), turnip (Brassica campestris L. (rapif era group) cv. Taibyohikari), and radish (Raphanus sativus L. (radicula group) cv. Commet) .
Comparing correlation coefficients and standardized partial regression coefficients of daily growth of plant part used as food on mean day temperature (DT), mean night temperature (NT), mean daily solar radiation (S), and mean daily maximum saturation deficit (SD), it was proved that DT or NT was the most promotive growth factor in leaf and fruit vegetables, while in root vegetables SD was the most promotive one on account of excessive root growth per day caused by shringing of root in the morning due to high SD. S was the most inhibiting growth factor in many cases.
In the plastic house, growth of cucumber fruit was greatly decreased by low humidity in the daytime. It was also observable in a air conditioning room in which air temperature was kept at 20°C but humidity was lowered from 90% at night to 72% in the daytime.
From these facts it was concluded that the negative effect of solar radiation on daily growth of plant part used as food of some vegetables growing in plastic house was due to low atmospheric humidity which showed a very high negative correlation coefficient with solar radiation.

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Recently chlorosis in leaves is frequently appeared in the greenhouse roses, and it depreciates rose cut flowers.
In this paper, the relationship between the appearance of chlorosis and soil chemical properties, some mineral contents in plant leaves was investigated. The results obtained were as follows.
1. The exchangeable CaO, MgO, K₂O and Mn were respectively contained in the ranges of 133-294 mg, 24.8-53.9 mg, 24.3-89.4 mg/100 g soil and 0.8-9.7 ppm in the cultivated soil of the greenhouses.
2. The concentration of extractable Fe was markedly low in a range of 2.3-5.2 ppm. On the contrary, available phosphorus indicated by Truog P was in a range of 144-332 mg/100 g soil and it was extremely abundant.
3. Correlation between the appearance of chlorosis and mineral contents in tested soil was not recognized.
4. The phosphorus content and chlorophyll in rose leaves showed a negative correlation at 1% level of significance.
5. It became clear from this investigation that the appearance of chlorosis was dependent on Fe deficiency induced by excess phosphorus in rose leaves and Fe deficient chlorosis was assumed to appear when phosphorus concentration in leaves was higher than 0.45%.

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