EFFECTS OF TEMPERATURE ON THE CIRCADIAN CONIDIATION RHYTHM OF TEMPERATURE-SENSITIVE MUTANTS OF NEUROSPORA-CRASSA

Period lengths at different temperatures and phase response curves at a high temperature (35 degrees C) of circadian conidiation rhythms were examined in 13 temperature-sensitive (un) strains of Neurospora crassa. Two strains, un-16 and un-18, had longer period lengths than the wild-type strain even at permissive temperatures. Period lengths of six strains, un-4, un-11, un-16, un-18, un-19 and un-22, changed differently from that of the wild-type strain at restrictive temperatures. However, the shape of phase response curves for high temperature (35 degrees C) for 3 h was almost the same for all un strains and the wild-type strain. We isolated 97 temperature-sensitive mutants with period lengths from 19.2 to 24.8 h and determined the dependence on temperature of the period length of the conidiation rhythm for each mutant. The mutants could be divided into four different groups in terms of their responses to changes in temperature.