Rhythm of sporulation within the section Penicillium clavigerum II. Induction of endogenous sporulation rhythms in Penicillium claviforme Bainier

The endogenous rhythm of sporulation occurring in Penicillium claviforme differs from the non-circadian one. 1. The rhythm period is long being equal to 30 h in cultures grown in light. In darkness, sporulation is uniform. 2. The rhythm is maintained for 3-5 periods, and then it vanishes which is caused by desynchronization of the hyphae. 3. Synchronization is resumed after photocycles become employed (Piskorz-Bińczycka and Jerebzoff. 1989). 4. The rhythm may be induced in darkness by supplying a certain dose of light energy. 5. The rhythm is sensitive to some components in the nutrient medium: a) asparagine as an agent strongly controlling the periodicity is responsible for the maintenance of the rhythm for a 3-week period. Asparagine controls also the length of the rhythm period, however it does not induce rhythm in darkness; b) biotine is responsible for shortening the rhythm period; c) avidin effects the length of the rhythm period and the regularity of the newly formed rings; d) the amino-acids used did not permit complete elimination of an addition of yeast extract to the nutrient medium the concentration of which was reduced to 50%.