Date: Mon, 1 Jun 1998 09:39:31 -0400 From: tjw@chos001.cho.ge.com (Tim Williams Ext. 5529) To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1874$foo@default> Subject: Re: Stratification
Some additional points to clarify my original posting on
stratification:
1. Seeds must be stratified moist. Dry stratification is not effective.
2. The change in the seed is chemical in nature. It is NOT the
imbibing of water and oxygen. Water and oxygen reach their max
levels in the seed during the first few days.
3. Stratification is only effective between 32 and about 50 F.
Temperatures below freezing cause the chemical reaction to stop.
4. The time required for complete release from dormancy is independent
of temperature or species. It requires between 2 and 3 months.
5. If freezing improves germination times, it is because freezing
causes micro-cracks in the seed coat which improves the rate
of water uptake. 2 minutes in water at 140 F is optimal for inducing
micro-cracks. See Deno's book for the exact procedure.
A correction, Deno's address is:
139 Lenor Drive
State College, PA
Tim Williams
tim.williams@cho.ge.com
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