Abstract
It has long been argued whether the permeability, Lp, of Chara, fresh water green algae, is anisotropic (Lp for influx is significantly larger than that for efflux).
In the present report I introduce a non-invasive with high temporal resolution (100msec) technique for measuring the change of turgor pressure in response to the step change of extracelluar osmotic pressure (Ogata 2004 submitted to PCP). Using this technique, it was found that there was no difference in Lps between influx and efflux across the plasma membrane. The apparent rectification in LpÅ@seems to be derived from; 1) the temporal change in concentration of the solute around the surface of membrane, the water motive force is changed; 2) the spatial deviation of the solute number along the length of the cell sap, a counter water motive force should be expected; and 3)the visco-elastic properties of the cell wall.
