Studies on semipermeability and electrical characteristics in membranes of Chara cells fixed with glutaraldehyde

When internodal cells of Chara corallina were incubated in a solution containing 1% glutaraldehyde, an increase in intracellular osmolality was observed, and this indicates that the plasma membrane maintained its semipermeability. The effect on the membrane potential was studied. Although the active component generated by the electrogenic proton pump was lost, the passive component (more negative than -100 mV) was maintained during glutaraldehyde treatment for more than 1-2 h. The membrane resistance increased significantly. It was found that the tonoplasts also maintained their semipermeability during glutaraldehyde treatment.