In Cedrus pollen adheres by microdrops to the apical portion of the in
tegument. The microdrops originate from dictyosome vesicles in cells o
f the integument apex. Electron-dense substances are present in these
dictyosome vesicles and accumulate between the surface cell walls and
plasma membrane. The substances traverse the walls and form microdrops
. The cuticle layer on the surface cell walls is less developed and do
es not serve as an obstacle to the passage. During pollination drop se
cretion, nucellar cells show characteristics such as undulation of the
plasma membrane, numerous dictyosomes, and a prominent amount of endo
plasmic reticulum. The cuticle layer is absent from the nucellar apex.
After the secretion, cell walls of the nucellus and chalaza become tr
ansparent. We describe ultrastructural changes associated with the win
ter dormancy of the ovule.