| Abstract: | The comparative study of Berberis stamen filaments and Mimosatertiary pulvini shows many common features in their corticalparenchyma ultrastructure. In both mature organs, cells haveunusual sinuous walls with numerous plasmodesmata, tannins inthe vicinity of the nucleus, microfilaments and microfibrilsin tannin vacuoles. Nevertheless, in Mimosa pulvini, the abaxialcells have thicker walls than the adaxial cells while in stamenfilaments the reverse is true; therefore the dissymmetric organizationof the organ walls is the opposite. We will discuss: (1) the problems of chemical fixation of excitableplant cells; (2) relations between the direction of bendingand the thickness of cell walls; (3) the location of tanninsand (4) the existence of microfilaments and microfibrils. Key words: Berberis canadensis Mill., berberry, Mimosa pudica L., sensitive plant, Stamen, Pulvinus, Ultrastructure, Seismonastic movement |
