Ultrastructural Observations on the Dikaryotic Haustorium ofCronartium Flaccidum(Alb. & Schw.) Wint. inVincetoxicum HirundinariaMedicus

Abstract

SUMMARY -The haustorium of the uredial stage of Cronartium flaccidum in Vincetoxicum hirundinaria was studied with TEM. The observations concern the haustoria! mother cell and its relation to the host cell wall, the penetration peg, the shape and the cytoplasm of the haustorium and some host cell organelles in relation to the haustorium. The presence of collars was noted. These features are similar to those described for host-dikaryotic haustorium relationship in other rusts. The extrahaustorial matrix however shows a unusual development. In fact, it wraps the whole length of haustoria! neck although it is separated from the haustoria! neck wall by the extrahaustorial membrane doubled in this region. The probable significance of this host-parasite interface, perhaps limited to the genus Cronartium, is discussed.

Penetration and early colonization in basidiosporederived infection on needles of Pinus pinea L. by Cronartium flaccidum (Alb. et Schw.) Wint.

“…These mor phological characteristics described for the two types of haustoria in the Literature cited, were observed for the dikaryotic and monokaryotic haustoria of C. flaccidum during the advanced colonization, already studied by LONGO and BRUSCAGLIONI (1986) on leaves of Vincetoxicum hi-rundinaria Medicus and by LONGO et al (1982) on primary needles and young stems of some species of the genus Pinus.…”