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Old 09-05-2003, 04:56 AM
Larry Dighera
 
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Default Pollinating Reed-Stem Epidendrums (Small Flowers).


Pollinating Reed-Stem Epidendrums (Small Flowers).

I chose reed-stem Epis for my breeding program, because they grow
quickly and do not require a greenhouse for culture in my locality.
What I didn't realize is that working with such tiny flower parts is
so difficult. My steady-handed jewlery-making skills and eyesight are
being tested by these minute flowers.

The aperture in the column is just about the same size as the pointed
end of a wooden toothpick. This makes it virtually impossible to
insert pollen with such an instrument, so I've resorted to using
straight pins, as they taper to an absolute point (unlike toothpicks).
The real difficulty is in seeing the pollenia and stigmatic opening
while attempting to accomplish pollination. It takes a 5X jewelers's
loop to provide adequate visual resolution (for me) to accomplish the
operation. But, the difficulty doesn't end there.

Coaxing the pollenia to stick to the straight pin long enough to
transfer to the stigma is accomplished by first placing some of the
sticky adheasive-like gel of the stigmatic surface on the pin point,
and then touching it to the pollenia. That often works too well, and
it is impossible to get the pollenia to release their grip on the pin
once they are finally in position. Frustrating.

If the nearly microscopic pollenia are accidently dropped, they are
usually forever lost. I've overcome that issue by placing a 5" X 8" X
1" shiny black plastic tray under the flowers I'm working with.
(These trays are available in the produce section of Trader Joe's
Markets, and are used to hold green beans.) But, because reed-stem
Epidendrums are so tall, it is necessary to place the tray on a
moveable shelf of the appropriate height to position it near enough to
the flowers. (Perhaps it would be more convenient to work with the
plant laying horizontally.) It is also necessary to work under bright
light; a two tube 4-foot fluorescent light provides virtually
shadowless illumination for the task.

Despite the aid of good light and magnification, it is not possible to
see if the pollenia have been optimally positioned on the stigmatic
surface. Attempts to remove parts of the flower to obtain better
physical and visual access have almost universally resulted in death
of the flower. But it's difficult to know if the cross would have
"taken," because my success rate is only about 25%. I'm finding the
success rate of intergeneric crosses to be significantly less.

Because the size of Cattleya pollen is considerably larger than the
caliber of the stigmatic orifice, I have tried two techniques:
removing flower parts to access the stigma, and trimming the pollenia
to size. Success has not been good.

I've read * that applying orange juice to the stigma before
pollinating may overcome the difficulty with intergeneric crosses, but
I haven't tried that technique yet. I've also read that it is best to
select young flowers (just, or coaxed open) for the female parent, so
I've started doing that.

Perhaps some of the sagacious members of this newsgroup with
experience in the techniques of pollinating small flowered orchids
would be kind enough to suggest additional options, or provide
pointers to appropriate articles and texts pertinent to this subject.
I'd be grateful.

Best regards,
Larry Dighera



*
http://www.geocities.com/~marylois/archiv18.html
The Trembling Toothpick: Basic Hybridizing
by Ed Wright