Cytoplasmic regulation of the interautogamous interval (IAI) in Paramecium tetraurelia.

Cytoplasm from individuals at different stages of the interautogamous interval (IAI) transferred into cells at constant clonal age (during the second half of the IAI) caused statistically significant changes in the IAI in clones initiated from recipients. Cytoplasm from the cells in the first half of the IAI caused prolongation of this period, cytoplasm from slightly older cells had no effect, while that derived from cells being a few fissions before the next autogamy shortened the duration of the IAI. This suggests that the cytoplasm of P. tetraurelia contains an autogamous immaturity factor retarding the occurrence of autogamy, and that at the end of the IAI there appears a component accelerating this process.