Q: How does a Venus flytrap sense prey?
One hair
Trigger hairs
A: Plants, unlike animals, do not have central nervous systems.
That does not mean, however, that they do not have the ability to sense their
surroundings. They lean towards light, send roots down to the ground, and probe
the soil for water sources. Plants are not the mindless vegetables people
accuse them of being!
Venus flytraps detect disturbances to their
leaves by means of "trigger hairs". These
trigger hairs are located on the trap leaves---there are about 3-5 on each
trapping lobe. If these are stimulated twice in rapid succession (within about 30 seconds), the ion concentrations in the leaves
increase. This results in an electrical
signal that propagates across the leaf. This signal tells cells in certain parts of the the leaf to change size
rapidly. This results in the closing of the leaves.
This is just a basic description---there are a huge set of complications
and details to this, but for that you must go to the next page.
Page citations: Juniper, B.E. 1989; Rice, B.A. 2006a; Schnell, D.E. 1976.
