Re: Stratification
ROBERT POGSON (robert.pogson@mwcs.mb.ca)
Sun, 08 Dec 96 11:13:00 -0600
C> From: "Zachary B. Kaufman" <zbk49255@challenger.atc.fhda.edu>
C>
C> I have a question for some biologists out there. I would like to
C> know what exactly is going on during seed stratification. I've
C> heard that putting seeds in the fridge for a month is enough
C> to cause them to germinate. Likewise, I've heard that to
C> stratify seeds, the seeds must be exposed to moisture during the
C> cold spell to germinate. And finally, I've heard the seeds must
C> be exposed to at least frost to germinate. What is the real
C> story here? What is going on in the seed during stratification.
C> What is the most optimal way of fascilitating this process?
Many seeds are produced in summer when the most resources are available
but by the time the seed is produced, growing conditions for seedlings
may be poor. Therefor, seeds may have a dormancy mechanism of several
forms. Some may have a hard shell to keep them from the environment till
the time is right. This shell may be broken by freezing (water expands as
it freezes) or abrasion or digestion in animals and birds. Some may have
a chemical dormancy which inhibits the production of some necessary enzyme.
The cycling of the seasons or available light and temperature may destroy
the inhibiting mechanism. Dormancies can be broken by simulating the natural
cycles or intervening by applying rooting hormone, brief exposure to high
temperatures or abrasion. Of course, one could place the seed in a natural
environment and let nature take its course, but this is not always possible
and it may be much less efficient in terms of time or yield. The bottom line
is to find or develope a recipe that works and use it.
... nfx v2.8 [C0000] Welders do it in all positions.