Our attempts to relate the bi-modal diurnal distributions to changes in
temperature and relative humidity failed. However, in our
case, the timing of the first pollen concentration peak agreed
well with that of a peak in direct solar radiant energy on the
anther when modeled as a vertically suspended cylinder.
This observation supported our hypothesis that solar
irradiance may be a driving force behind corn anther
desiccation and dehiscence. For days on which bi-modal
pollen concentration distributions were measured, the data
further suggested that the dip in pollen concentration after
the first peak was synchronized with a large decrease (30%)
in mean velocity.