"Neural capacity" in Mimosa pudica: a review.

A selective review of the rapid movement displayed by the “sensitive” plant, Mimosa pudica is presented. This paper attempts to elucidate the similarities that exist between animal systems and the plant Mimosa. Various fundamental analogies are described as follows: (1) Mimosa, like animals, displays behavioral plasticity or modification in response to specific stimuli; (2) Mimosa contains specialized structures which play roles similar to various structures associated with animals. Specialized phloem cells in Mimosa constitute a conduction pathway not unlike a simple nerve in animals. Mimosa motor organs display properties similar to animal muscles. All specialized structures enable Mimosa to exhibit morphological movements via stimulus induction; (3) The mechanisms involved in the animal and Mimosa response appear to be similar at a physiological and biochemical level. These primarily being (a) transmission and propagation of electrical potential, (b) ionic exchange, (c) membrane permeability modification, (d) cation involvement, (e) use of transmitter-like substances, and (f) energy dependence; (4) Similar effects are induced by various chemical agents in Mimosa and animals. Based on these similarities it is suggested that the plant Mimosa contains a neural capacity which manifests itself through a simple “nervous system.” Theoretical interpretations are presented which attempt to relate current psychobiological research to factors involved in Mimosa pudica. The use of Mimosa as a subject of investigation in the neurosciences at the classroom and laboratory research level is stressed.