Abscisic acid induces a cytosolic calcium decrease in barley aleurone protoplasts.
Cytosolic calcium concentrations (Cai) of barley aleurone protoplasts after stimulation with the plant hormone abscisic acid (ABA) were measured by using the calcium-sensitive fluorescent dye Indo-1. The measured basal Cai is about 200 nM. Stimulation with ABA induces a strong dose-dependent decrease in Cai to a minimal value of about 50 nM. This decrease occurs within 5 s. The Ca2+ antagonists La3+ and Cd2+ inhibit the ABA-induced Cai decrease in a dose-dependent manner, while the Ca2+ channel blockers verapamil and nifedipine give no inhibition. The induction of Cai decrease by ABA is consistent with activation of the plasma membrane Ca2(+)-ATPase by ABA. The possible role of this ABA-induced Cai decrease in ABA signal transduction and in counteracting the effects of gibberellic acid are discussed.
Wang
M
M
Centre for Phytotechnology RUL/TNO, Department of Molecular Plant Biotechnology, Leiden, The Netherlands.
Van Duijn
B
B
Schram
A W
AW
D000040:Abscisic Acid / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000096:biosynthesis*; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation; D005456:Fluorescent Dyes; D001467:Hordeum / Q000187:drug effects*; D007211:Indoles; D009543:Nifedipine / Q000494:pharmacology; D011523:Protoplasts / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology
D005456:Fluorescent Dyes; D007211:Indoles; D000040:Abscisic Acid; D014700:Verapamil; D000252:Calcium-Transporting ATPases; D009543:Nifedipine; C048960:indo-1; D002118:Calcium