| Popis: |
Auxin modifies the electrical transmembrane potential of isolated protoplasts according to an inverted bell-shaped dose-response curve (Ephritikhine et al, 1987; Shen et al, 1988). The sensitivity of plant protoplasts to auxin can be characterized by the hormone concentration inducing the maximal variation of the transmembrane potential difference (ΔEm). On tobacco mesophyll protoplasts, the response to auxin was blocked by antibodies directed against an auxin-binding protein (ABP) from maize coleoptile membranes, or raised to the plasmalemma ATPase from yeast (Barbier-Brygoo et al, 1989a). The auxin-induced ΔEm thus seems to nvolve the occupancy of an auxin receptor at the cell surface which in turns would activate the proton-pump ATPase at the plasmalemma. |
