Date: Fri, 8 Dec 2000 10:10:49 -0800 From: Ivan Snyder <bioexp@juno.com> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg3536$foo@default> Subject: re: Byblis Carnivory Evolution
Robert Gibson replied:
>I like your idea on the widespread nature of the carnivorous syndrome in
non-carnivorous plants. I have not seen the >nub of tissue on cotyledons
of Drosera or Dionaea seedlings, but certainly know of many cases of
Drosera which >show cryptocotylar germination eg D. glanduligera and all
tuberous Drosera. It would make sense that there would >be the option to
absorb nutrients through a process of digestion and assimilation. How
does this process differ from >that of the processes of pollen
germination on the stigmas and the subsequent growth of pollen to the
ovary? I do not >know the technical side to this so am curious to know if
the process if assimilation of seed reserves via the >cotyledons is
similar to the triggers for pollen germination and growth and how both of
these compare to true >carnivory, particularly by way of chemicals
produced and pathways of nutrients. Any ideas how you would test this?
Ivan again:
I do believe the stimulation by pollination which causes a histamic
response may have been relocated and is now used in the triggering of
digestive fluid secretion in carnivorous plants. This in my mind is a
separate matter.
>I'm not so sure that Byblis "leaves" are modified cotyledons, but this
is just a gut feeling. Do you know of any >anatomical studies in the
genus in which the internal structure of these structures have been
examined, including the >nub at the leaf tip. Without internal details
this part of your theory seems a bit harder to sell. Why could the nub at
the >leaf tips not just be the transferred nub from the cotyledons now at
the tips of true leaves?
There was one past CPN article which tried to explain the nub which has
vascular tissue. This article did not make much sense to me. It just
seems more reasonable that the leaves are replaced by cotyledons since
they are identicle in appearance and also this explains the presence of
the nub on both. I'm thinking of investigating seedlings of other
non-carnivorous sticky plants which grow in wet conditions to see if
their cotyledons might remain functionally carnivorous.
Ivan Snyder
Hermosa Beach
California
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