Plant communication/sensing references wanted
ajt at rri.sari.ac.uk
Fri Dec 18 19:06:13 EST 1992
In article <921218151818.MIN-LNTAa20035.bionet-news at uk.ac.daresbury> you wrote:
: In article <1992Dec16.001934.23792 at gserv1.dl.ac.uk> ajt at rri.sari.ac.uk writes:
: [...mimosa pulvinus mechanism discussion deleted...]
: >The analogy with propagation of nerve impulses in animals is often
: >cited in descriptions of these responses, and ion-transport is
: >certainly involved in the turgor mechanism of the pulvini. However,
: >electrogenic proton extrusion is the fundamental ion-transport process
: >in plants and the active Na+/K+ exchanges that occur in transmission of
: >nerve impulses do not occur in plants.
: This is interesting...apparently there is some disagreement in this area?
The fundamental ion-transport process in plants is widely accepted to
be electrogenic proton extrusion by membrane-bound ATP-ases (in effect
a reversal of chemi-osmotic ATP synthesis according to Mitchell's
hypothesis). See for example Poole, R.J. 1978, Energy coupling for
membrane transport, Annual Review of Plant Physiology, 29, 437-460.
The other ion-transport processes are driven indirectly by the
resulting electrochemical potential gradients and moderated by
selective permeability of the membrane to different ions.
Although net Na+/K+ exchanges are observed in plant cells (Na+ efflux
and K+ influx) the Na+/K+ antiport found in animal cells does not occur
in plant cells, to the best of my knowledge. I'm sure Bill will
correct me if Na+/K+ antiport has been demonstrated in plants ;-)
Dr. A.J.Travis, | Tony Travis
Rowett Research Institute, | JANET: <ajt at uk.ac.sari.rri>
Greenburn Road, Bucksburn, | other: <ajt at rri.sari.ac.uk>
Aberdeen, AB2 9SB. UK. | phone: 0224-712751
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