plants, sense-organs of. 2
Plate X, Figs. 1 and 2 (cropped to square)
illustrating R. A. Robertson. “The Sense-Organs of Plants,” Communicated October 27, 1909. Transactions of the Edinburgh Field Naturalists’ and Microscopical Society 6 (1907-12) : 164-172
Smithsonian copy, scandate 20110719
Darwin’s results were fully confirmed in 1894 by the work of Czapek (‘Annals of Botany,’ 1894). Ozapek’s experiment consisted in inducing the root to grow into a small glass boot in such a manner that the root-tip — presumably the sense-organ — was held at right angles to the motor area — the sub-apical region. When the seedling was supported so that the tip was vertical, there was no curvature; when supported so that the tip was horizontal, curvature took place in the motor area, bringing the apex—the percipient organ — back to the vertical, the position of geotropic equilibrium.
A successful repetition of Ozapek’s experiment is illustrated in Plate X., figs. 1, 2. ...
tags: curvature; flower-pot saucers; geotropism; rotation; R. A. Robertson (1909)