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

The rate of cyclosis, the value of resting potential and theexcitability were studied on the Nitella internode whose cellsap was replaced with artificial solutions. K⁺ to Ca⁺⁺ ratioin the cell sap should be within 2 to 50 in order to maintainthe normal rate of cyclosis and the resting and action potentialsat least for several days. Replacement of the cell sap witha solution containing Li⁺, Na⁺ or Rb⁺ in place of K⁺ had noappreciable effect on the activity of the internode for severaldays, while gradual but marked decrease in the rate of cyclosisand the resting potential was observed with Cs⁺. There was noappreciable difference between the effects of Cl^– andNO₃^– on cyclosis, resting and action potentials, whileSO₄^–– decreased them to some extent. The rate ofcyclosis was not affected appreciably by changes in osmoticconcentration between 0.17 and 0.30 M. (Received September 6, 1963; )