Rapid Hormone-induced Hyperpolarization of the Oat Coleoptile Transmembrane Potential.
The effects of the plant growth substances indoleacetic acid (IAA) and fusicoccin on the transmembrane potential of Avena coleoptile cells (at 27-29 C) were studied. Fusicoccin caused hyperpolarization of the membrane potential which started after a lag of less than 20 seconds, and which on average reached -49 mv at an external K(+) concentration of 1 mm and -75 mv at 0.1 mm K(+). IAA caused a hyperpolarization of -25 mv starting after a lag of 7 to 8 minutes. These results suggest that fusicoccin and IAA both activate electrogenic H(+) extrusion.
Cleland
R E
RE
Department of Botany, Washington State University, Pullman, Washington 99163.
Prins
H B
HB
Harper
J R
JR
Higinbotham
N
N