by Piter Kehoma Boll
It’s been a long time since I updated the blog, as you might have noticed, but time is really something I don’t have much lately. I just came back from Argentina yesterday after taking part in COMPORTA 2013, the first Argentinian Congress of Behavioural Biology. Among the several works presented, there was one, by researcher Dr. Monica Gagliano from the University of Western Australia, about memory and learning… in plants!
Well, I’m not here to talk about this subject, but I intend to do a post about this as soon as possible. I want to introduce here the species used by Dr. Gagliano in her study: the touch-me-not Mimosa pudica.
Neotropical in origin, i.e., native from Central and South America, the touch-me-not is widely known by its capacity to fold its leaves inwards when touched, as a possible mechanism to avoid predation. It’s interesting because most plants (except insectivores) doesn’t show such a quick movement.
In many places, the touch-me-not is cultivated for this charming way to move, and it has also become naturalized all around the world, being considered an invasive species mainly in Southeast and South Asia, Pacific Islands, Tanzania and Australia.
This rapid folding of leaves happens through an action potential running through the plant leaf and reaching a structure at its base, called pulvinus, which makes some cells lose water and thus folding the leaf. Action potentials are basically an electrical current passing through the membrane of a cell. They are far more common in animals, being essential for neurons and muscle cells, but are rare in plants, though existent in some, like the touch-me-not. What if some complex structure like this one could lead, someday, to the evolution of more complex behaviors in plants? Wouldn’t that be cool?
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ROBLIN, G. (1979). Mimosa pudica: A Model for the Study of the Excitability in Plants. Biological Reviews, 54 (2), 135-153 DOI: 10.1111/j.1469-185X.1979.tb00870.x
Wikipedia: Mimosa pudica. Available online at: <http://en.wikipedia.org/wiki/Mimosa_pudica>. Access on April 19, 2013.