Physiology of Rapid Movements in Higher Plants

Among the various behaviors in higher plants, a peculiar one, that a part of the leaf or flower in certain plants shows very rapid movement upon stimulus, has invited the attention of a number of investigators since the beginning of botanical research. However, in spite of this long history of study, numerous fundamental aspects of the phenomena remain to be clari­ fied. Since the definition of the rapid movement is still unclear, discussion in this review will be restricted to three types of the movements: (a) rapid response in the pulvini of the mimosas; (b) shutting movement in the traps of two carnivores, Dionaea and Aldrovanda ( an aquatic plant); and (c) visible movements in the stamen and pistil of some plants upon stimulus. This review is not intended to be a comprehensive resume of all published works on the movements. I intend to restrict my discussion to a consider­ ation of various results in an attempt to discover a general mechanism un­ derlying these movements, and will stress the relation between electrical re­ sponse and the movement. Several reviews and monographs have been published that approach this problem from various points of view (18, 19, 24, 42, 101, 103 ) , including the author's own works (11, 71) . In this review I will return to some of the important older literature which provides a basis for understanding the mechanism.