Structure of the stigma and style in Colletia and Discaria (Rhamnaceae: Colletieae)

摘要

The ultrastructure of the stigmas and styles of Colletia paradoxa, Colletia spinosissima, and Discaria americana was studied by transmission electron microscopy before and during anthesis. The purpose of the study was to contribute a full description of possible interactions between the male gametophyte and the sporophytic tissues of the stigma and the style. Ultrastructure changes in the stigmatic papillae and epithelial and sub-epithelial cells of the stylar channels in relation to pollen tube growth are discussed and compared between species. New pollen tube pathways are described for hollow styles.