Distinct Pathways of Regulation Seed Dormancy and Germination by Abscisic Acid

Abscisic Acid (ABA) is the phytohormone inducing seed dormancy, whereas seed germination occurs at low ABA concentration. Two pathways of their regulation are considered. One represents ABA reception and its signal transduction to ABA-responsive genes to induce dormancy genes, a modification of this way leading to germination in the absence of ABA. Another way suggests direct ABA inhibition of plasmamembrane H+-ATPase in dormant seeds that prevents germination and its activation in the absence of ABA, thus promoting seed germination.