Re: Topics
From: Andrew Wheeler <awheele2@abacus.bates.edu>
In response to Karl's email, as far as I know, the seeds themselves are not
treated. There are a variety of methods currently used to treat seedlings and
as far as I know, all involve using seedlings with between 2-4 fans. Some
variations involve room temperature treatment for 24 hours, others near freezing
temperatures for up to five days. The mechanism of action for colchicine is to
disrupt mitosis so the chromosomes replicte but do not divide, then when it is
washed out after the treatment period, the cells replicate and divide as normal,
with double the normal number of c-somes. Treating seeds would likely not yield
any consistent results because the cells aren't dividing.
As far as treating living plants, it has been tried by some by scooping out
the meristem (growth point) and adding colchicine with a number of different
beardless species, but they only produce sectional chimeras of varying ploidy
levels that get overgrown by the rest of the healthy, normal cells.
Perhaps treating tissue cultured plantlets would work, but I don't know
anybody that has tried.
Andrew Wheeler
At College in Maine, where it snowed .5 inches friday night
Karl Miller wrote:
> From: "Karl Miller" <karlkate@valuelinx.net>
>
> At non iris meeting, the speaker (a large commercial rhododendron grower)
> mentioned they are using colchicine to improve rhodies. I asked him if they
> were treating the seeds and the answer was no. All their propagation is via
> tissue culture and they treat the tissued sprouts and looked for changes and
> improvements as they grew the plant on.
> Is this a new time in the plant cycle that could be adapted to Iris and
> other perennials? Would you treat as the roots germinate or as the leaves
> are at certain stages? No idea what % solution would be needed. Don't think
> it would need to be as strong as for seed treating as you would not be
> dealing with the seed coat. What about treating rhyzomes?
> Maybe some is already doing this but I have only heard about soaking the
> seeds.
>
> >From a sibrob lurker
> Karl Miller
> In Arkansas where it is a "cool" low '80's and the is sun shining.
> ----- Original Message -----
> From: Bill Dougherty <103225.2126@compuserve.com>
> To: sibrob <sibrob@onelist.com>
> Sent: Tuesday, November 09, 1999 2:57 PM
> Subject: [sibrob] Topics
>
> > From: Bill Dougherty <103225.2126@compuserve.com>
> >
> > Hello everyone!
> >
> > Not much talk lately so I thought I would throw out some topics:
> >
> > SSI - Society for Siberian Iris
> > Improvements?
> > I threw out the topic of a speaker bureau?
> > Master irisarians classification?
> >
> > Best Siberians by color class
> > Blue
> > White
> > Red
> > Yellow
> > Pink
> > Purple
> >
> > How do you use colchicine (sic) to induce tetraploidy with seed?
> > Are there other methods?
> >
> > I. typhifolia
> >
> > What was your experience with it this year. Any interesting crosses bloom
> > this year?
> >
> > List of strong growing Sibs, List of weak growers?
> >
> > Has anyone tried to clone Siberians?
> >
> >
> > Bill Dougherty
> > Fridley, MN.
> >
> > Record high temps for November - 78 yesterday, global warming????????? Do
> > not want to water dormant rhizomes!
> >
> > >
>
>
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