Properties of action potentials in Drosera tentacles.

Action potentials of Drosera tentacles resemble those of vertebrate peripheral nerves in that they appear to be comprised of relatively uniform spikes, variable shoulders or negative after-potentials, and variable positive after-potentials. The peaking of the spike corresponds to a period of great refractoriness, while action potentials of low amplitude may be fired readily during the negative after-potential. The action potentials fired during the negative after-potential appear to be unlike those of peripheral nerves in that they are of abnormally brief duration. Also apparently different from the case in peripheral nerves is the dependence of the duration of an action potential on the interval separating it from the preceding action potential.Action potentials propagate from the neck of the stalk to its base at about 5 mm s(-1) at room temperature. Propagation may be reversed artificially, consistent with the possibility that the neuroid cells are electrically coupled.