Re: CULT: vernalization

Bill Shear wrote:
> 
> This is an adaptation that is needed because there are two appropriate
> photoperiods each year which could initiate flowering in a plant.  However,
> a plant that flowers normally in the spring would probably not be able to
> mature its seeds if it flowered at the equivalent photoperiod in late fall.
> By having a chilling requirement preceding the appropriate flowering
> photoperiod, such mistakes are avoided.

Thanks Bill for the answers. I had often wondered how a plant could
distinguish between the vernal and autumnal photoperiods, and knew of
chilling periods needed for things like (eastern) liliacs, pistachios,
apples, etc. but hadn't tumbled to the combination of events as a
survival tactic. "Ain't nature wunnerful."(sic)

Brings a question (thought, postulate, whatever) to mind. In regards to
rebloomers, perhaps the vernalization process is missing and they
responded with faster growing rates to compensate for its lack. Or maybe
they didn't need to develop (or maybe lost) the protective mechanism
because they grew so fast. 


John                     | "There be dragons here"
                         |  Annotation used by ancient cartographers
                         |  to indicate the edge of the known world.

John Jones, jijones@ix.netcom.com
Fremont CA, USDA zone 8/9 (coastal, bay) 
Max high 95F/35C, Min Low 28F/-2C average 10 days each
Heavy clay base for my raised beds.
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