Electro-osmotic and biopotential measurements on phloem strands of Nymphoides.

Electroosmotic measurements on the excised vascular strand from the petiole of the water plant Nymphoides peltatum have been carried out, and the Onsager coefficients obtained. About 120 water moleculer per ion are carried electroosmotically when the strand is in 10(-4) M KCl, about 30 in 10(-1) M KCl. Potential measurements made on an intact and functioning petiole are discussed in the light of the pressure-flow and electroosmotic theories of translocation.