Fig. 4.

High-frequency temperature cycles cannot elicit demultiplication in the absence of functional frq. frq⁺ and frq-null strains were subjected to temperature cycles (T) whose durations ranged downward from the circadian range, as indicated on the far left of the figure. Whereas frq⁺ is able to demultiply to 18-, 20-, and 24-h periodicities, and free-runs in shorter duration cycles, both frq-null strains show conidiation being driven by temperature cycles for all T's applied. On the right of each profile is the period length (in hours) ± 1 SD estimated from at least six race tubes. Similar experiments yielded equivalent results independently in two laboratories; data reported are from one laboratory.