Phototropic and Geotropic Responses During the Development of Normal and Mutant Fruit Bodies

Tropic responses occur during the development of fruit bodies of the basidio-mycete SchizophylZum commune. The stipe (stage IJ) formed from the masses of aggre-gated cells (stage 1);was positively phototropic to light of wavelengths 420 and 540 nm but not 600 or 660 nm. The apical pit (stage III) was positively geotropic and the development of gills (stage IV) occurred in response to gravity so that the gilled surface faced downwards. The expansion of the pileus (stage V) was negatively geotropic