The negative surface charge density of plasmalemma vesicles from wheat and oat roots

Abstract

Plasmalemma vesicles were isolated in a sucrose‐containing medium from wheat and oat roots and the net negative surface charge density was determined with 9‐aminoacridine fluorescence [Chow, W.S. and Barber, J. (1980) J. Biochem. Biophys. Methods 3, 173‐185]. The outer surface of the vesicles (measured in the presence of sucrose) had densities of − 16 to − 20 mC·m −2 and −29 mC·m −2 for wheat and oat roots, respectively. The inner surface ‐ presumed to be the cytoplasmic side and calculated from the values measured in the presence and absence of sucrose ‐ was more negative, and its size depended on the salt status of the roots.