POLLEN-STIGMA INTERACTIONS FOLLOWING COMPATIBLE AND INCOMPATIBLE POLLINATIONS IN HAZELNUT

Scanning electron microscopy was used to describe pollen-stigma intera ctions during compatible and incompatible pollinations of hazelnut (Co rylus avellana L.), a species possessing sporophytic self-incompatibil ity. The stigmatic surface is of the dry type and was covered with elo ngated, rounded papillae. Compatible and incompatible pollen hydrated within 2 hours of pollination. Compatible pollen tubes emerged by 4 ho urs and grew into the style by 12 hours after pollination. Penetration of stigmatic papillae appeared to be intracellular in some cases. In incompatible pollinations, however, pollen tube emergence was delayed until at least 8 hours. The pollen tubes were distorted and did not pe netrate the stigma.