herbicide damage

[Diane Whitehead]

One small area of the garden with yellow elwesii has herbicide
damage this year.  I assume that is what has turned the leaves
yellow, as there is a patch of newly-seeded lawn beside the
snowdrops.

One herbicide is used by amateur plant breeders as a mutagen
to increase the number of chromosomes.  I wonder if these
plants may have had their pollen or ovules affected.  I will
collect seeds from them to see.

[johnw]

Diane

I got very excited about a find of variegated Acer rubrum near one of the Universities here.  They later reverted and I found out the variegation was a reaction to the spraying of Roundup.

I treated some bamboo seeds 10 years ago with the pre-emergent herbicide Surflan.  Somewhere I have the instruction sheets but as I recall it wasn't a complicated procedure. Those bamboos are still under 20" and in 2 gallon pots, the controls are 12 feet or more high. I hear there is an 80% success rate doubling chromosomes amongst certain perennials but I was assured there would be 0% success rate with monocots and bamboos in particular as they can quickly escape the affected parts and re-shoot as 2n. 

I'd be interested to hear how one would go making tetraploid bulbs with chemicals.  Is there a stage in twin-scaling that might just do the trick?

johnw

[rob krejzl]

John,

If you look back through the galanthus thread you'll find some refs to using very dilute oryzalin and other methods to achieve polyploid states. I think one of the problems with trying to use oryzalin on twin-scales would be the high probability of mixoploids being produced, but the Summer 2008 edition of the American Rhododendron Society did discuss a method which might be worth exploring. A summary was posted to the Yahoo Lily List in July '08:

Dear Members:
For those of you who are trying to induce polyploidy,
there is a description of a "new" method described in the most
recent Journal of the American Rhododendron Society. (Summer 2008)
The ARS does post some of the articles from the Journal on their
website, but this one probably won't be posted for some time.

Briefly, they used Surflan AS (40.4% oryzalin) diluted
to produce 50uM oryzalin with 5.5 g/L of agar at 50degrees C.
The Oryzalin/agar suspension was dripped onto newly germinated
seedlings. The drop solidified on the cotyledons of the
seedlings, and allowed contact of the oryzalin. The treatment
was repeated at four day intervals, with two to four treatments
giving conversion rates of 20-80%, some to as high as 8N, as
determined by flow cytometry. Seedlings were kept at 100%
humidity and under continuous light for the treatments.
There appeared to be fewer cases where the outer layer of the
plant was affected while the inner layers, where the sex organs
originate, was not be affected.

Rhododendrons and lilies are quite different, but this
approach might be useful to some people. I haven't tried a
websearch on this method, but it might be worth trying.

Ken

[johnw]

rob - That's much the same recipe I got from an acquaintance back in the 90's. With perennials it was suggested to soak the seeds just as the roots and cotyledons were emerging from the seed coat.   I forget how long but they then had to be placed under running water for a few hours before planting.

I found the original document, if anyone is interested PM me.

Doubled Galanthus would be interesting to see, but how to achieve is the question?

johnw