XVI International Botanical Congess

One component of the guard cell response to abscisic acid (ABA)is inhibition of the inward potassium channels that mediate potassium uptake during stomatal opening. The role of both calcium-dependent and calcium-independent pathways in transducing this inhibition, and the plausible involvement of heterotrimeric G-proteins as signalling molecules in the ABA response will be discussed. Recent cloning of novel Galpha-like proteins in our laboratory and further characterization of a guard-cell ABA-activated protein kinase(AAPK)will be reported.