Observations on the gynoecial pathway for pollen tube growth in sweet lowbush blueberry (<em>Vaccinium angustifolium</em> Ait.)

Abstract

Gynoecial structure in sweet lowbush blueberry, Vaccinium angustifolium Ait., was investigated in order to characterize the pollen tube pathway in order to provide a framework for further studies on pollination and fungal infection. Closed flower buds and pollinated open flowers were collected from managed lowbush blueberry fields in Colchester County, Nova Scotia, Canada. Following chemical fixation, the tissue samples were examined histologically using light and scanning electron microscopy. The continuous pathway was characterized by a fluted, exudate-filled stylar canal that connects the wet stigmatic surface with the exudate covered surface of the ovarian placentae. Following pollen deposition and germination, tubes growing along the pathway eventually arrive at the micropyles of the anatropous ovules; ovule penetration by pollen tubes and fertilization of the female gametophytes ensue. The pollen tube pathway of this taxon conforms to the general pattern reported from other ericalean taxa.