Action spectra for fruiting of the mushroom Coprinus congregatus

Spectral sensitivity for photostimulated and photoinhibited phases of the development of Coprinus congregatus Bull. ex Fr. was determined from 405–730 nm. The cultures were exposed during 12 h to a constant number of incident quanta. Spectral sensitivity for photoinduction of primordia formation, for photoinhibition of primordia development and for photomaturation of primordia was quite similar, suggesting a common photoreceptor during fruit-body morphogenesis. A defined action spectrum for the photoinhibitory effect of a light break during the inductive night was determined from 407–690 nm. The most effective wavelengths were in the blue (445 nm). Wavelengths longer than 510 nm were ineffective. The general shape of this action spectrum was similar to those obtained for many blue light responses in which a flavoprotein was postulated to be the photoreceptor.