STUDIES ON NITELLA HAVING ARTIFICIAL CELL SAP II. RATE OF CYCLOSIS AND ELECTRIC POTENTIAL

Abstract

The rate of cyclosis, the value of resting potential and the excitability were studied on the Nitella internode whose cell sap was replaced with artificial solutions. K⁺ to Ca⁺⁺ ratio in the cell sap should be within 2 to 50 in order to maintain the normal rate of cyclosis and the resting and action potentials at least for several days. Replacement of the cell sap with a solution containing Li⁺, Na⁺ or Rb⁺ in place of K⁺ had no appreciable effect on the activity of the internode for several days, while gradual but marked decrease in the rate of cyclosis and the resting potential was observed with Cs⁺. There was no appreciable difference between the effects of Cl⁻ and NO₃⁻ on cyclosis, resting and action potentials, while SO₄⁻⁻ decreased them to some extent. The rate of cyclosis was not affected appreciably by changes in osmotic concentration between 0.17 and 0.30 M.