Electric Control of Polarity in Plants

i- The P.D. along stem pieces of Bryophyllum calycinum and of Coleus hybrida var. Bertha Grosze T mu is influenced by ether. . no lethal quantities of ether are applied, no “loss” of P.D. p ated. Either a positive or a negative variation of the inherent •u- occurs. From this it is concluded that the bio-electric potentials, measured in our experiments, are not redox poten- 3- No Q10 is found. Only a short-lasting influence of alterations of the temperature is observed. We therefore conclude that the potentials measured are not due to chemical processes. 4. It is shown that the P.D. can be influenced considerably by the motion of water into — or out from the cells. 5. From these results it is concluded that the potentials in our objects are diffusion potentials according to Osterhout. 6. In the roots of Vicia Faba the zone of maximal growth coincides with the most positive potential. 7. The regenerating petioles of Coleus leaves negativate during the first days after isolation. After 5 days they positivate. 8. As a rule the basal nodes of Bryophyllum stem pieces are negative during the first time after isolation. In Coleus this phenomenon is much clearer. 9. Gravity only partly influences the P.D.-variations during regeneration. 10. No redistribution of water in stem pieces could be stated; this factor is not responsible for the alterations of the P.D. in regenerating stems. 11. Hetero-auxin, applied basally in lanolin paste 0,5 %, accelerates and regulates the spontaneous variations of the P.D.’s in regenerating stem pieces of Coleus. When applied apically, however, the normal P.D.-alterations are disturbed. 12. It is concluded that in initial regeneration typical changes of the membranes at the base occur. In the new apex such a specific reaction could not be detected. The investigations were carried out in the Botanical Laboratory of the State University, Utrecht. I owe much to Prof. Dr. V. J. Koningsberger for his interest in my work and his valuable criticism.