. Practical text-book of plant physiology. Plant physiology. 108 RELATION OF PLANTS TO ELECTRICITY which roots of Phaseolus seedlings turn toward the cathode is at a temperature of 200 C. If the strength of the current is in- creased beyond this, mechanical effects due to the disturbance of the conditions of turgidity are produced which may cause a cur- vature in the opposite direction. Such curvatures are not to be ascribed to electrotropism. The maximum currents for Helian- thus are 8, and Lepidium, d. Sporophores of Phycomyces exposed to the action of Hertzian waves curved away
. Practical text-book of plant physiology. Plant physiology. 108 RELATION OF PLANTS TO ELECTRICITY which roots of Phaseolus seedlings turn toward the cathode is at a temperature of 200 C. If the strength of the current is in- creased beyond this, mechanical effects due to the disturbance of the conditions of turgidity are produced which may cause a cur- vature in the opposite direction. Such curvatures are not to be ascribed to electrotropism. The maximum currents for Helian- thus are 8, and Lepidium, d. Sporophores of Phycomyces exposed to the action of Hertzian waves curved away from the source of the rays much after the manner of apophototropic curvatures.' 167. Electrotaxis. The movement of the entire body of an organism in such manner as to constitute locomotion, in response to currents passing through the medium in which it is found, has. a Fig. 50. Cell with walls of rubber and clay for testing electrotaxis of motile or- ganisms. The electrodes are seen to be applied to the clay walls, and the organisms are aggregated near the kathode. After Verworn. been observed only in animals, but the method of investigation is given here with the idea that repeated tests with motile zoo- spores and other free moving plants may secure some positive re- sults. The following method will show the electrotactic move- ments of paramoecium in a very striking manner. 1 Hegler, R. Ueber die physiologische Wirkung der Hertz'chen Electricitatszellen auf Pflanzen. 1892. Loeb, J. Ueber die physiologische Wirkung elektrischen Wellen. Arch. Ges. Physiol. 69 : 99. 1897. Brunchorst, J. Die Funktion der Spitze bei den Richtungsbewegungen der Wurzeln. Galvanotropismus. Ber. d. Deut. Bot. Ges. 2: 204. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original MacDougal, Daniel Trembly, 1865-1958. New York [etc. ]
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