Environment Control in Biology

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New born, infant, and adult mice, rats, guinea pigs, and rabbits were exposed to simulated altitude of 5, 000m to 8, 000m for 150 minutes or exposed repeatedly to simulated altitude of 5, 000m for 150 minutes a day for six days. Daily changes of the body weight during exposure period were observed and effects of the acute exposure to altitude on growth of the animals were investigated. Experiments were carried out in spring and summer seasons, which temperature and humidity in the low pressure chamber during experiment were maintained within the range of 22°to 26°C, and 70 to 72%, respectively. Ascending rates were 900 to 1, 000m per mi flute. Experimental results were as follows:
1. Single exposure to altitude of 5, 000m for 150 minutes did not show any decrease of the body weight change in all ages and kinds of the animals.
2. Repeated exposure to altitude of 5, 000m for 150 minutes a day for the period of 6 days showed small retarded growth in all animals in compared with control animals.
3. Single exposure to altitude of 8, 000m for 150 minutes showed the same retardation in body weight growth as in the case of repeated exposure to 5, 000m for 6 days.

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Flower bud of Cymbidium virescens usually differentiates in June, and the flowering season is fromMarch to April in the next year. In this paper studies on the accerelation of flowering and elongation of flower stalks are reported.
The materials were collected in Aichi Prefecture in 1960. The results obtained were as follows:
1) The plants kept in a greenhouse after low temperature treatment at 5°C for two months (Nov.8, 1961-Jan.7, 1962) elongated their flower stalks normally and successively flowered on Jan. 29, 1962. However, low temperature treatment for one month (Nov.8-Dec.7, 1961) was not effective.
2) The flowering was accelerated in high temperature (20-30°C), but elongation of flower stalks was not recognized. Flower buds withered when night temperature was above 20°C.
3) Long day treatment, sprays of gibberellin (10, 50, 100ppm) or IAA (10, 20ppm), and fumigation of ethylenchlorhydrin have no effects on flower-forcing of this plant.
It was concluded that the elongation of flower stalks of Cymbidium viresceus was accelerated with low temperature treatment and that the flowering of this plant was accelerated in high temperature.

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