Plant communication/sensing references wanted

Rich Young young at serum.kodak.com
Fri Dec 18 09:54:40 EST 1992


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?
  I lifted the following from a different newsgroup written by Bill Williams
  of St. Mary's College of Maryland in message <13812 at umd5.umd.edu> in
  reference to mimosa pudica:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sensing of environment:  I'm not too sure what the actual sensing mechanism is,
but the signal is an action potential, just like in an animal's neurons.  A
charge separation propagates along the cells, causing sodium and potassium
channels in their membranes to open and close, which alters the membrane
potential and thus passes the signal along to the next patch of membrane. 
Plant action potentials are usually much, much slower to propagate than animal
action potentials.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  Clearly, there is a fundamental difference of opinion regarding the action
  of Na+ and K+ in this area...either that, or my ignorance is showing, which
  is entirely possible.  :-)

[...]

>I would be interesed to know if rapid ion-mediated responses of plants
>to external stimuli are related in any way to the evolution of a
>nervous system in animals?

  Me, too, although my feeling is that there may be some parallel evolution
  at work.


-Rich Young (These are not Kodak's opinions.)



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