Mature pollen of Annona cherimola. (A) Intine (black arrow) is similar all around the pollen grain, but exine (white arrow) is thinner in the pollen aperture site. Longitudinal section stained with a 3:1 mixture of Auramine and Calcofluor. (B) Sibling pollen grains have a faint cohesion that showed with JIM 5 antibody the presence of unesterified pectins. (C) Mature pollen tetrad following acetolysis. (D, E, F) Mature pollen observed with scanning electron microscopy (SEM). (D) Mature pollen grains with a globose shape and a radiosymmetric disposition. (E) Exine cohesion helps keeping sibling pollen grains together. (F) Pollen exine shows a tectate perforate appearance. A, B, D: Bar = 20 μm; C: Bar = 10 μm; E, F: Bar = 2 μm.