Figure 3.

Pollen development within the tapetal chamber in Annona cherimola. (A) Two young microspores in a tetrad which still keeps the pollen mother cell wall. Aperture sites are located towards the outside facing the pollen mother cell wall. (B) Pollen is shed free, within the PMC wall, in the tapetal chamber. Within this confined space the young microspores turn (C) with their aperture sites facing now each other as the PMC cellulosic wall is digested. (D) The pollen grains regroup sticking through the aperture sites, and enlarge as the tapetum degenerates. Longitudinal anther 2 μm resin sections stained with calcofluor and auramine. Bar = 20 μm.