Re: HYB: Pollination
- Subject: Re: HYB: Pollination
- From: L* M*
- Date: Wed, 22 May 2002 16:56:04 -0400
From Bill Shear, Oct 21, 1997:
<Experience shows that only one style arm or stigmatic lip need be
pollinated to get a full pod. However, one pollen grain can only
fertilize one ovule. Thus if only a very small amount of pollen were
applied, not all the ovules would be fertilized. Pollen grains are so
small that so long as a visible amount is applied to the stigmatic lip,
there should be enough to pollinate all the ovules.
There are caveats. In wide crosses, it is wise to use as much pollen as
possible and pollinate all three lips, since
various kinds of
incompatibilities will render most of the pollen
ineffectual. The more
pollen, the greater the chance of getting a seed.
Curiously, pollen grains are actually whole individual plants--the males
of
the gameteophyte generation. Each grain contains
only a few cells. Some
of these cells produce the pollen tube. When the
pollen grain reaches a
compatible stigma, it germinates and a long tube
quickly grows down through
the stigmatic tissues to reach the ovules (the
unfertilized seeds within
the ovary). Two sperm nuclei then travel down
this tube. One fertilizes
the egg in the ovule, and produces the embryo
plant, and the other
fertilizes the endosperm, or stored food tissue,
within the seed (this is
actually a triple fusion, so the endosperm is
3N).>
Reposted by Linda Mann
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