Subject: InRe> Scraped Strawberry

From: [email-masked] (Walter Schmid)
Date: 29 Mar 1995 08:46:47 -0800

Subject:    InRe> Scraped Strawberry
On the subject of strawberry ripening which has been discussed recently, I
believe that it is the developing embryo in the seed which is inside the
achene ("strawberry seeds") that is the source of auxin which then induces
development of the desired fleshy receptacle tissue behind. Originally the
pollen is a source of auxin to start the process. 
I believe that the original (?) work on this topic was done by J.P.Nitsch
many years ago when he was working on ripening in strawberries and in
gherkins while at the Phytotron in Pasadena, California. It seems to me
that the paper describing this work was in American Journal of Botany and
had to be no more recent than the middle '50s. 
The phenomenon has been illustrated in figures found in many textbooks. We
currently use 'Biology of Plants' (5th ed.) by Raven, Evert, and Eichorn
(Worth Pub. 1992) in our basic plant biology course. In that book, Figure
25-7 on page 551 shows a normal strawberry and also one in which no 'seeds'
were allowed to remain and where various arrangements (rows) of 'seeds'
were allowed to remain. The result is malformed strawberries. 
Applying IAA instead of allowing pollination to occur also induces a
developing strawberry but it has no viable 'seeds' on it. 
The new book 'Botany' by Moore, Clark, and Stern (W.C.Brown Pub. 1995) also
illustrates this in Figure 18.5 on page 421. 
Hope this helps. 
Walter E. Schmid
Plant Biology
SIUC