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Journal of Experimental Biology 31,68-75 (1954)
Published by Company of Biologists 1954

The Physiology of Contractile Vacuoles : IX. Effects of Sudden Changes in Temperature on the Contractile Vacuole of a Suctorian; With a Discussion of the Mechanism of Contraction

J. A. KITCHING ¹

¹ Department of Zoology, University of Bristol

1. A study has been made of the effects of sudden changes of temperature on the contractile vacuole of the suctorian Discophrya piriformis Guilcher.

2. A sudden increase of temperature from below 15° C. by 5° or more causes a temporary fall in the rate of output, followed by a rise to a new level higher than the original. During the depression in activity the body swells slightly.

3. The vacuolar frequency increases immediately but briefly when the temperature is raised, falls steeply when the depression sets in, and when secretion is re-established rises again to a level above the original.

4. A sudden fall in temperature causes an immediate decrease in vacuolar frequency, followed by a partial restoration. The rate of output falls rather more slowly and remains low. In several cases a small decrease in body volume was observed.

5. It is suggested that the contractile vacuole is really contractile.

6. The observations on vacuolar frequency described in this paper are interpreted in terms of an inherent vacuolar rhythm which is modified by temperature and which is partially linked with rate of secretion.