Date: Fri, 29 May 1998 10:02:35 -0400 From: tjw@chos001.cho.ge.com (Tim Williams Ext. 5529) To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1846$foo@default> Subject: Stratification
>> From: "Sundew Sundew" <sundew@HOTMAIL.COM>
>>
>> Just wanted to let you guys know that I recently received some S minor
>> and purpurea v seed which I decided to plant and put in the freezer for
>> 2 days in an attempt to stratify it. Its now a couple months later and
>> all ive got is 1 venosa seedling!!! I am sure I would have been better
>> off planting the seed without any stratification at all. oh well....
>>
>> MH
>
>MH (or Matt),
>
> 2 days in the freezer is not stratification. Scarification, perhaps,
>but Sarracenia don't need that treatment. Try a couple weeks in the
>fridge. If the seeds are frozen, I don't know that stratification will
>even happen.
>
>Dave Evans
>
There has been a lot of talk lately about stratification in this group.
Let me introduce the group to the work of Dr. Norman Deno at Penn State.
Dr. Deno has spent the last 20 years or so studying the mechanisms
involved in the release from dormancy in seeds. To date he has studied
around 8000 species.
The stratification mechanism functions identically in ALL seeds requiring
it. Dr. Deno has found that the temperature threshold is around 50 F.
He uses 40 F (standard refrig temperature) for his experiments. He has
also found that release from dormancy begins after 2 months and is
complete by 3 months Time is independent of temperature provided it is
remains below 50 F. The only effective stratification is 3 months at
40 F or less. Freezing is NOT required.
I don't have Dr. Deno's book with me, but in it he lists the germination
requirements of 8000 species including many CPs. He does list Sarracenia,
but I don't remember which conditions they require. Many plants will
germinate with no treatment if the seed is fresh and require
stratification or some other treatment if the seed has been stored. This
may be the case with Sarr., it would certainly explain the variable
results.
Dr. Deno's books, "Seed Germination - Theory and Practice", describes
all known dormancy mechanisms (there are about nine) and the most
effective treatments for release (germination). They also include
listings for 8000 species and their germination requirements. Successful,
greater than 85%, germination has been achieved with all but six or so
of the 8000 species.
Smoke as a promoter of germination was mentioned several days ago. The
third volume of the book, published in Jan., covers smoke. Several
different promoters were found in smoke. Some species respond to
increased potassium. Others are responding to various gibberilins.
GA3 will substitute for smoke for most, but not all smoke release seeds.
The others appear to require specific gibberilins. There are hundreds
of known compounds with gibberilin activity, so finding the right ones
is a bit of a chore.
Dr. Deno's book (3 volumes so far) can be obtained directly from him:
Dr. Norman C Deno
123 Lenoir Drive
State College, PA.
Tim Williams
tim.williams@cho.ge.com
This archive was generated by hypermail 2b30 : Tue Jan 02 2001 - 17:31:32 PST