542 Calculations of Potentials in Nitella

Protoplasmic Streaming of an Internodal Cell of Nitella Flexilis

The sudden cessation or sudden decrease in velocity of the protoplasmic streaming of Nitella flexilis is observed whenever an action potential is elicited. The action potential can be generated by an electric stimulus after its refractory period, whether the flow is at a complete standstill or on the way to recovery. The membrane potential is generally decreased more or less when the rate of fl...

Electroosmosis in Nitella

The role of electroosmosis was studied directly in Nitella. The cells were mounted in a water-tight barrier between two chambers containing reversible electrodes for the application of potentials, and fitted with calibrated capillaries to measure water movement. No water movement was found when small existing bioelectric potentials were short-circuited through an external connection, nor when e...

Na and K Fluxes in Nitella clavata

Na and K influxes and effluxes, membrane potentials, and cell ion concentrations of Nitella clavata were measured as functions of external NaCl concentrations and time. It appears necessary to conclude that active K transport into the cells as well as active Na extrusion is present, although the latter is of small magnitude and possibly is explicable as exchange-diffusion. An attempt has been m...

The Relation of the Membrane Potential and Resistance of Nitella to Ion Fluxes

The Influence of H+ on the Membrane Potential and Ion Fluxes of Nitella

The resting membrane potential of the Nitella cell is relatively insensitive to [K](o), but behaves like a hydrogen electrode. K(+) and Cl(-) effluxes from the cell were measured continuously, while the membrane potential was changed either by means of a negative feedback circuit or by external pH changes. The experiments indicate that P(K) and P(Cl) are independent of pH but are a function of ...