Ionic Relations of Marine Algae III. Chaetomorpha: Membrane Electrical Properties and Chloride Fluxes

Abstract

In the large coenocytic cell of the marine green alga Chaetomorpha darwin ii, the electric potential difference, .pvo, between the vacuole and the outside seawater can have either of two distinct states, a positive, and more usual state, with .pvo = +5 mY, and a negative state with .pvo = - 29 m V. The p.d. across the plasmalemma of the cell was approximately -72 mY, and the difference between the positive and negative states occurred at the tonoplast with .pvc = + 77 m V or + 43 m V respectively. In the change from the positive state to the negative state, the electrical resistance of the plasmalemma increased from 510 to 750 n cm2 , and the resistance of the tonoplast increased from 4900 to 7100 n cm2