Electrical Events in Growing Lepidium Root Tips Seem to be Correlated with Gravitropic Dynamics

Abstract

In the root of a higher plant, the mechanism to perceive gravity, and transduce it into a physiological signal, is located in the statocytes of the calyptra. A prerequisite for the induction of the graviresponse of the Lepidium root is the integrity of structural polarity of the statocytes (ref. see Sievers, this Vol.). Recently, electrophysiological experiments have been carried out to approach the molecular mechanism of graviperception and transduction (Behrens et al., 1985b, Behrens et al., 1982, Behrens and Gradmann, 1985). To discuss electrical phenomena at the plasma membrane of root cells, the contribution of different ions to electrogenesis was investigated. Association of these results with data yielded from gravitropic reaction kinetics (Behrens et al., 1985c), and structural changes after external electrical field application (Behrens et al., 1985a) may hold for the idea that transduction of a gravistimulus primarily consists of electrical events, which even might be the signal transmitted from the statenchyma to target cells which trigger graviresponse.