Re: Re: HYB:Colchicine
> I think there are indeed improvements to be made, but it is highly
> unlikely that they will be made by converting diploid varieties to
It depends on what you consider an improvement.
I appreciate the way that modern bearded irises developed, but I don't
see that that development precludes further diploid to tetraploid
conversion. As you point out, most of the work was done by tenacious
hybridizers who smeared a lot of pollen and fortunately they
occasionally smeared an unreduced gamete. By 1925, most TB introductions
were tetraploid, long before colchicine was used in plant breeding.
Although colchicine was first extracted in 1820 and was used medically
soon after, it wasn't until 1955 that the absolute configuration was
known. It was "discovered" by plant breeders in 1934. It wasn't until
1937 that chromosome doubling was reported with colchicine. I would be
willing to bet that had those early iris breeders known about
colchicine, they would have used it.
Because of fortuitous events, bearded irises got a jump on many species
in development of "modern form". For the last half century, iris
breeders have stuck to crossing and selecting, while the rest of the
plant breeding world has tried to figure out ways to not duplicate, but
surpass the events that occurred with irises in other species. The
brightest and best in potential plant breeders are going to go where
there is money or where there is interest. Obviously, the money is in
food crops, while the interest is in daylilies and hosts.
Plant breeders quite often go back to species to try to bring up
favorable traits (such as disease resistance) and there is no reason
that the same should not be done with bearded irises. Of course, the
issue of tetraploidy makes it more difficult, but it should not preclude
the attempt. Starting with the best of recent introductions may help win
earn awards within the AIS, but it is most unlikely that it is going to
produce a truly great garden flower.
One of the problems is that most TB's conform to the "Modern Form".
Those of us who grow beardless irises, where "near species" forms are
welcome, know that they frequently out perform the highly selected
cultivars. With near species irises such as 'Shaker's Prayer' and
'Bellender Blue' (a BIG species) winning awards, it is obvious that
there is a place for older forms. Sharon Whitney observed that the most
popular Japanese irises at her open garden are usually near species. It
is interesting to me that some of the most popular irises at our local
show have been historics and aribreds which lack the form that we have
come to expect with TB's.
In a recent conversation with Currier McEwen, I posed a question about a
possible technique for tetraploid induction with Japanese irises.
Although my idea may be a little far fetched, his response was "It might
work. I don't think I have the time, so why don't you try it and get
back to me?" It's that attitude that defines a true visionary, a person
who can see that every idea deserves to be explored.
> Do you know what it does to lungs and livers?
Yes, Carryl, I do know what it does. I happen to be a pharmacist with
over 25 years experience. The way it damages lungs is if you snort it
and get the stuff into the lung. You may be interested in reading up on
particle size and the techniques that are employed to get drugs deep in
the lungs. It's not as easy as you may think. As for the liver,
colchicine is used clinically to PREVENT further deterioration of the
liver in chronic liver failure! Fortunately, in my patient base I've
only seen it used for this condition twice.
I recognize that my background may make me better prepared to handle
colchicine safely, however, I do NOT believe that it makes me uniquely
prepared. During that time, I have taught many people to give
injections, including some who were visually impaired, crippled with
arthritis or mentally challenged. I believe that someone who can master
such skills as baking a cake, eating a meal with a knife and fork
(instead or wearing it), collecting pollen and keeping their hands away
from their face should be able to handle colchicine safely.
> You're definitely wrong to equate Digitalis (foxglove) as a garden
> plant with a concentrated extract that is known to be highly toxic.
As for digitalis in the garden versus colchicine in my lab, I'll use an
argument I heard a few years back.
A toxicologist from MIT testified that incinerator ash leachate is safe
because with modern (there's that word again) liners, it would never get
into the soil, ground water or water supply. She never answered on the
basis of its toxicology. Of course, she was evading the truth. I don't
deny that colchicine is much more toxic, based on weight and lack of
antidote. My point is that the chance of digitalis poisoning from a
in the garden is much higher than the chance of colchicine poisoning
when properly handled in the lab.
Colchicine is most harmful when ingested or inhaled (which isn't that
easy to do). Simple precautions can prevent either. That includes
wearing a mask when handling the dry form, avoiding spraying the
solution, packaging only in laboratory
glassware, labeling and disposing properly. I would not use it around
food or food containers and I keep it in a locked chemical cabinet or in
a refrigerator which contains no food. I do not allow anyone in my lab
when I'm using it. Incidentally, the United States Dispensatory, 20th
edition (1918) warns in italics "Great caution must be used in tasting
it and then only in very dilute solutions." I don't think they went far
enough in guaranteeing the safety of the druggist.
Digitalis toxicity depends on the species and the glycoside content of
the plant, which varies according to the growth conditions. Based on
pharmaceutical reference standards, toxic dose may be less than 3 grams
in an adult. Although it is bitter, unfortunately, some children do not
recognize it as such. Even drinking the water that the flower was in can
be deadly. Furthermore, it has been mistaken for comfrey and brewed
into a tea. There are more than 100 digitalis plants in my garden. I try
to make all tours of my garden guided, but that does not always happen.
Though the likelihood of digitalis poisoning is remote, it is real...but
it's not real enough to make me dig them up.
Happy New Year.
R. Dennis Hager
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