Fragrance
Nolo Contendre (Wed, 14 Apr 2004 11:30:34 PDT)

John,

If a recessive allele becomes fixed in a population it is usually not a
random event - something is exerting selection pressure that gives the
plants with the recessive allele some reproductive advantage so that they
set more seed than those without it. In the case of floral characters such
as fragrance, that is almost always pollinator mediated selection.

Alan
----- Original Message -----
From: "John Bryan" <johnbryan@worldnet.att.net>
To: "Pacific Bulb Society" <pbs@lists.ibiblio.org>
Sent: Wednesday, April 14, 2004 1:42 PM
Subject: Re: [pbs] Fragrance

Alan;
What do you understand "natural selection" to mean? How do you relate
this to fragrance? Cheers, John E. Bryan

Nolo Contendre wrote:

"The colonies in North Africa were of the type that allowed
the gene to surface and were thus fragrant. "

John - this still isn't a reason to counter pollinator selection

pressure in

North Africa for fragrance. Or do you not believe in natural selection?

Alan Meerow
----- Original Message -----
From: "John Bryan" <johnbryan@worldnet.att.net>
To: <pbs@lists.ibiblio.org>
Sent: Wednesday, April 14, 2004 12:47 PM
Subject: [pbs] Fragrance

Dear All;

Mary Sue posed a question regarding fragrance in some plants in the

same

species having fragrance and others of the same species not having any
fragrance.

I do not think this has anything to do with pollinators, rather
geographic variation. I remember discussing this with Professor
Doorenbos in Wagening, The Netherlands, back in 1956, when I was

living

and studying in The Netherlands. He told me that Cyclamen hederifolium
from North Africa had a distinct fragrance, while others from other
regions of the Mediterranean did not. His opinion was that the gene
carrying the fragrance character was present in all of the species but
recessive. The colonies in North Africa were of the type that allowed
the gene to surface and were thus fragrant. No doubt other colonies

with

fragrant flowers were to be found in isolated pockets within the

natural

range of the plants, but all from North Africa were fragrant. This

seems

to me to be a logical reason. If it were due to pollinators the
variations and ability to adapt to a particular habitat would mean

that

even greater variances in fragrance would be apparent. Cheers, John E.
Bryan
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