Release of an inhibitor of stipe elongation from illuminated caps of Coprinus congregatus mushrooms

Inhibition of stipe growth by a substance or substances produced in the cap of Coprinus congregatus fruit bodies cultivated in continuous light has been confirmed. Caps in which maturation was induced or prevented were transferred to decapitated stipes from normally growing sporophores. Stipes were most sensitive to inhibition when treated 16–18 h before maturity. Caps from continuous-light primordia only a few hours older than the photoinhibited stage were most inhibitory. When normal primordium maturation was induced by darkness followed by light, the inhibitor disappeared from the caps 18–20 h before maturity.