Temperature Effects on the Resetting of the Phase of the Neurospora Circadian Rhythm

Various temperatures relative to a 25°C control have been applied as phase-resetting agents in release-assay experiments using the conidiation rhythm of the mold Neurospora crassa. The larger the difference in temperature from the 25°C control, the stronger the phase-resetting effects. Phase- resetting curves of the weak type (type 1) are observed for temperatures up to 28°C and down to 22°C, whereas temperatures above 28°C and less than 22°C generally cause phase-resetting curves of the strong type (type 0). Singularity behavior occurs at approximately 22°C and 28°C when 25°C is used as the control temperature. When a different control of 29.5°C is used in a release-assay experiment and the resetting temperature is 25°C, near-singularity behavior is observed.