Effect of electrical fields on polar growth of Phycomyces blakesleeanus

Abstract When Phycomyces blakesleeanus spores germinated in an electrical field of 10–20 V · cm⁻¹, the hyphal tips showed a strong tendency to grow towards the cathode in a medium with pH 7. A similar response was found during growth at pH 5 but a maximal response was only obtained at higher field strength. Also the emergence of the germ tubes from the spores could be polarized by such fields but the degree of polarization was much smaller at pH 7 and almost nonexistent at pH 5. Ionic strength of the medium did not play an important role since only minor differences were found in media with 0, 1 or 10 mM KH₂ PO₄ as the only salts. The results suggest that a voltage-dependent rearrangement of (membrane) proteins affects the polar growth of the fungus.