[Pollinator] Nature's Chastity Belt (for beans)

[Peter Bernhardt]

Dear JIM:

Thank you for sending the link.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2701803/pdf/mcn106.pdf
 Let me share it with colleagues and students.  I see you found the section
in Materials and Methods describing what the authors had to do to
hand-pollinate each flower.

Prior to pollen deposition the stigmatic surface was rubbed with a brush in
order to release stig- matic fluids.

Here is the perfect reason why entomologists and botanists always need to
work together on field studies in pollination ecology.  Thanks to the
research of Yolande Heslop-Harrison, and her colleagues, botanists have
known about the thin but strong pellicle that covers the pistil tip of most
cross-pollinated, papilionoid legumes (peas, beans, clovers. alfalfa, etc.)
for at least 35 years.  Now, every bee-keeper knows that honeybees
pollinate crop and garden legumes but "tripping" the flower but few know
what the weight and pressure of the insect does to the protective coat
(pellicle) on the pistil tip.  The weight of the "right" insect ruptures
the pellicle making it receptive to incoming pollen.

Remember, almost all papilionoid legumes are bisexual and anthers open and
release pollen in the flower bud so the pellicle is nature's chastity belt
(and probably more efficient than the human hymen).  If an insect of the
wrong size and weight lands on the keel petal containing the pistil then
nothing happens.  Cross-pollination can occur only when the appropriate
pollinator contacts the keel petal and that petal rubs against the tight
pellicle.

As luck would have it, Steve Callen (Allison Miller Lab, St. Louis U.) is
completing a competitive, research poster for this April on a local legume.
 Part of the poster will show how the pistil tip resembles an angry, red
pimple (pellicle intact) and becomes a pollen accepting "funnel" (pellicle
ruptured).

PETER
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sonic.net/pipermail/pollinator/attachments/20130321/d4b8aaa6/attachment.html>