CAPACITY FOR DIFFERENTIATION OF SETAE AND OTHER HYPHAL TYPES OF THE BASIDIOME IN EXPLANTS FROM CULTURES OF THE POLYPORE PHELLINUS-CONTIGUUS

Explants between 20 and 250 mm3 in volume from dark-grown colonies of Phellinus contiguus on 2% malt extract agar were used to investigate the capacity of different colony regions for photoinduced differentiation of basidiomal hyphae. Differentiation at the surfaces of explants from competent colony regions was autonomous, requiring only moisture and light. After 3-4 d seta density was enhanced by both excision and light whereas differentiation of basidia and dissepiment building hyphae required a light trigger and tended to be reduced by excision. On the explant surface which was the air/agar interface of the original colony, maximum differentiation of all hyphal types was restricted to a narrow band centred approximately 1-2 mm behind the position of the colony margin at light exposure, and also to the edges. On those explant surfaces which were exposed by cutting there was good development of all three hyphal types on non-marginal colony regions whereas mainly setae differentiated on near-marginal regions.