Circadian Rhythms of Potassium and Sodium Contents in the Growing Front ofNeurospora crassa

摘要

The temporal changes of potassium (K+) and sodium (Na+) contents in the growing front ofNeurospora crassa(al-2, bdstrain) grown on solid medium showed circadian rhythms which persisted for at least 45 h in the dark. The K+content reached a maximum at about 10 and 30 h after the transfer from light to darkness, while the Na+content was at a minimum at these times. Both the rhythms were set off by the light to dark transition and were not observed in constant light. The phase of the circadian rhythm of conidiation of this strain was delayed by 5 h by exposure to 50 min of white light (photon fluence rate 20.7 W/m2) 7 h after the light to dark transition. The same exposure significantly changed the ratio of K+to Na+content in the growing front measured 8 h after the exposure.