Water Permeability of a Characean Internodal Cell with Special Reference to Its Polarity

Abstract

Water permeability (hydraulic conductivity) of the Nitella internode was studied by means of transcellular osmosis with special reference to its polarity. It was shown that the change in turgor or in cell volume involved in transcellular osmosis is ahnost over within 5 sec after the onset of both forward and backward osmoses. What is different with respect to turgor between the two osmoses is its final level. In forward osmosis the turgor drops down to a definite level depending on the external concentration, while in backward osmosis the turgor invariably comes back to the normal level.