In 16 cases out of 18 experiments, a significant induced lag time was exhibited, Table 1. Therefore the hypothesis of an instantaneous adaptation of germination conidia of P. chrysogenum should be rejected. The lag time did not differ significantly from zero for two up-shifts experiments, but the instant and the magnitude of the shifts were different. The analysis of variance showed a significant effect of the magnitude of the shift, Table 3. The instant of the shift was also of paramount importance, due to its interactions with the two other factors. For example, downshifts experiments were characterized by the greater, l ผ 7.11 h and the smaller, l ผ _4.32 h, induced lag times for 3/4, 10 _C amplitude, and 1/4,15 _C amplitude, respectively, Table 1.