Viable pollen
The average percentage of viable pollen showed little differences
among the different species (Figure 1). There seems to be no correlation
between viable pollen with the fruit set. Pollen adhesion on the stigmatic
surface involves both impaction and the subsequent formation of
attachment bonds [7]. According to Clarke et al. [8] on initial contact,
the adhesive components could be contributed by either or both the
partners, to enhance mutual adhesion. The specificity needed for
foreign pollen discrimination might be provided by adhesive base or
the thickening agents, both high molecular weight components (protein
and carbohydrates) (Figure1).