Ultrastructure of teliospore formation in the rust fungus Puccinia podophylli

Abstract

Teliospore initials of Puccinia podophylli develop from binucleate sporogenous cells lining the base of the telium. The teliospores are formed in basically the same fashion as those of other rusts that have been examined at the ultrastructural level. The long, straight or slightly curved spines present on mature teliospores initially develop as slight bulges or protrusions on the spore surface. The spore wall in such a region then evaginates to form a slender spine that is initially filled with cytoplasm. The cytoplasmic material is then progressively excluded from the tip of the spine as a result of the thickening of the spine wall. Mature teliospores of P. podophylli possess a wall consisting of a thick, outer, electron-dense layer in which stratification is only rarely visible and an inner thinner, less electron-dense layer.