Re: [Inducing tetraploidy--the magnolia method?]
- To: s*@onelist.com
- Subject: Re: [[sibrob] Inducing tetraploidy--the magnolia method?]
- From: R* H*
- Date: 31 Jan 00 17:35:32 PST
From: Robert Hollingworth <Cyberiris@netscape.net>
Well, the magnolia method sounds like a good idea in theory, but you won't
find any cotyledon for the drops of solution to collect in with Siberian
seedlings. Also it's not so easy to get siberian seeds to all germinate
together so that you can spray them en masse. I seem to remember someone
trying to get away from root effects by sticking the germinating seedling
shoot first into vaseline containing colchicine, but I expect it didn't work
for some reason since there was no follow up. I believe that DMSO is probably
rather critical since it enhances the uptake of the colchicine into the plant
system. I wouldn't worry too much about toxicity, particularly if you don't
inhale the spray very much. I have used DMSO applied to the smin as a near
miraculous way of getting rid of bruises for a number of years and am still
around (occasionally smelling garlicky I guess). I'm not aware that it has an
severe toxicity -- I know several vets that do the same and use it on animals.
They're selling an close analog for relieving arthritis pains at the moment.
If anyone does try thois, plese share the results. 100% conversion or anything
like it would be a breakthough. Bob
rdhager@dmv.com wrote:
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A friend of mine who is interested in magnolias sent me an article "An
easy and effective method of cholchicine treatment" by August E. Kehr.
It was published in "Magnolias and Their Allies", David Hunt, ed. 1998.
The method described makes a lot of sense and the rate of conversion
(chimera) and survival he reports is incredibly high.
He uses 0.025% colchicine in aqueous solution with 0.5% by volume DMSO
and 1/10th drop of dish-washing liquid. The seed are started in a normal
potting soil. After they germinate, just as the first true leaves
appear, the colchicine solution is misted over them until a minute
amount collects in the crevices between the cotyledons. They are kept in
high humidity and misted with the same solution daily for 7-10 days.
Kehr reports that he can convert magnolia seedlings to polypoids with
"almost 100% success"! That's a boast that I haven't heard from iris
growers.
Currier describes the high casualty rate that he has experienced as
being due to destruction of the primary root system and the failure of
the treated seedling to develop a secondary root system. Since this
system would avoid direct contact of the colchicine with the root
system, it may reduce the main cause of casualties!
A few caveats before we all put this colchicine/DMSO solution in our
ultrasonic nebulizers:
Colchicine is EXTREMELY toxic, both to plants and animals. Be sure to
wear a good filter mask and gloves before spraying this stuff. Take it
outside and stay up wind of the spray!
DMSO is an industrial solvent and has enjoyed an ill-founded repuation
as an analgesic balm for at least 20 years. It is used occasionally in
large animal veterinary practice. When applied to the skin, it
penetrates immediately and can be detected as a garlic-like odor in the
exhaled air of the user. There have been attempts to use it in humans to
enhance topical drug absorption, but it has not proven to be an
acceptable. I'm not sure that it is a necessary component of this spray
and would be tempted to try it without the DMSO.
Have anyone out there used a method similar to this one? Does anyone
want to try?
Thanks.
R. Dennis Hager
on Delmarva--where the icestorm did little damage.
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