FACTORS AFFECTING TRANSLOCATION AND SCLEROTIAL FORMATION IN MORCHELLA-ESCULENTA

Morchella esculenta was grown on square split plates, forming scleroti a on one side and mycelium on the other. After the fungus ceased to co lonize and before sclerotial initials appeared, [C-14]3-O-methyl gluco se was added to the edge of the plate on the mycelial side. The effect of various activities in the mycelium (source) and sclerotia (sink) o n sclerotial formation and translocation were examined using inhibitor s and water potential changes of the media. Sodium azide or cyclohexim ide applied separately to both sides inhibited both sclerotial formati on and translocation, showing that processes in the source and sink de pend on metabolic activities as well as protein synthesis. The use of nikkomycin inhibited sclerotial formation, without affecting transloca tion to the sclerotia. Since the hyphal tips swelled and burst, the tr anslocated compounds were lost to the media. In a strain defective in sclerotial formation, used as a control, no translocation took place, showing that there is a connection between sclerotial formation and tr anslocation. Reversal of the water potential gradient between the two media (lower on the mycelial side), reduced the formation of sclerotia and translocation to them. Translocation to Morchella sclerotia takes place via turgor driven mass flow, but is nevertheless affected by ac tivities in both the source and the sink. (C) 1995 Academic Press, Inc .