The ontogeny of perithecia in Guignardia bidwellii

International audienceThe ontogeny of perithecia in Guignardia bidwellii was studied with contaminated berries and under in vitro conditions. The first developmental stage consists of a stromatic envelope surrounding a carpocentrum in which an ascogonial apparatus (composed of ascogonial cells and trichogynes) differentiates at the second stage. Stage 3 is marked by the incipient formation of the ascal locule and development of pseudoparaphyses. At the subadult stage ( = stage 4) these filaments intermingle with asci and they are progressively stretched owing to ascus expansion. The mature ascocarp (stage 5) contains numerous eight-spored asci and opens through an apical ostiole. The developmental features of Guignardia bidwellii indicate a pseudoparaphysate ascolocular type of development. Consequently, the fungus is more correctly placed in the Botryosphaeriaceae than in the Mycosphaerellaceae

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