Fig. 5. Swelling of a vesicle derived from the contractile vacuole complex of a P. multimicronucleatum cell that took place after the vesicle had previously decreased to its minimum size in an increased external osmolarity of 1 mol l^–1 sorbitol. (A) A series of pictures of the vesicle showing swelling. The white arrow in a points to the shrunken vesicle. (B) Time course of swelling of the vesicle. Vesicle volume is presented as the percentage of its maximum volume in the increased osmolarity. Letters a–j in B show the times when the pictures in the corresponding frames in A were taken. The straight line is the linear approximation of the increase in vesicle volume. Scale bar, 50 µm.