Further Studies of Electro-Osmosis inNitellain Relation to Pores in Membranes

By measuring the number of water molecules per ion which were moved electro-osmotically through cells of Nitella translucens and N. flexilis it has been shown that a significant difference existed between samples of these species in 1965. In each species the electro-osmotic efficiency was greater with Na+ than with K+. Also io-4 to io~5 M IAA tended to decrease electro-osmotic efficiencies while IAA, after 30 min. treatment, produced a significant increase in water flow into the treated end of a living cell. Calculations based on this work suggest that about io8-io9 pore sites per cm2 exist on the surface membranes for Na+ or K+ ion transport.