Leaf disks (1.0 cm in diameter) of tender-green mustard (Brassica campestrisL. var. perviridisL. H. Bailey) grown under controlled environmental condition were incubated on water in the light (13, 000 lux) or in the dark at 25°C for 4 days.
During incubation L-ascorbic acid content of the leaf disks rapidly increased in the light and decreased in the dark. Peroxidase activity increased in the dark during incubation, but the increase of activity was considerably suppressed in the light.
On the other hand, the fall in levels of chlorophyll and protein during incubation was observed in both light and darkness. The result indicates that senescence of leaf disks proceeds during incubation.
These suggest that the change in peroxidase activity during senescence of leaf disks of tender-green mustard is closely related to L-ascorbic acid content affected by light.
The differences between disks cut from old and young leaves were also studied about the changes in the contents of L-ascorbic acid, chlorophyll, protein and peroxidase activity during incubation of the leaf disks, but there was no significant difference in both disks.

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The role of physical contact in the induction of irregularities in the estrous cycle of grouped mice and the hormonal control of the production of the operative stimulus were investigated. Thirty females unisexually housed in a cage in contact with each other exhibited prolongation of the estrous cycle; by contrast, 30 females individually housed in the compartments of a partitioned cage exhibited normal estrous cycles. Increasing the cage density to 50 females resulted in a further increase in the incidence of prolonged cycles. An intact female housed in free contact with ovariectomized or orchidectomized conspecifics exhibited a high percentage of prolonged cycles whereas an intact female prevented from having physical contact with gonadectomized conspecifics exhibited normal estrous cycles. The results emphasize that physical contact between individuals plays a major role in the induction of estrous cycle irregularities in unisexually grouped females and that ovarian hormones are not involved in the production of the estrous cycle-disrupting stimulus.

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The optimization of illumination conditions with fluorescent lamps was studied to collect basic data for the reduction of light power consumption in a plant factory.
1. A cylindrical growth chamber with higher light reception was developed which houses on its periphery a vertically arranged array of fluorescent lamps.
2. A semi-logarithmic plot of the fresh weight of lettuce (Lactuca sativaL. cv. Okayama saradana) against cultural time gave a straight line with a correlation coefficient of 0.99.
3. The lettuce grew acceleratedly at a CO₂concentration of 350 ppm under a light intensity of 250 μE·m^-2·s^-1: the fresh weight was doubled in two days.
4. The effect of CO₂concentration on the growth rate was hardly appreciable over a range of 350-4, 000 ppm at high light intensity of 250μE·m^-2·s^-1but remarkable at a low light intensity of 85μE·m^-2·s^-1.
5. The growth rate seemed to be saturated at light intensity of 85μE·m^-2·s^-1which is about a quarter of the saturation light intensity observed with the conventional, downward illumination. The optimum temperature under illumination from all direction was higher than that of the downward illumination.
6. The ratio of fresh weight of leaves to that of roots was higher under lower light intensity.

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