title: Ca2+signalling in stomatal guard cells.
abstract: Ca(2+) is a ubiquitous second messenger in the signal transduction pathway(s) by which stomatal guard cells respond to external stimuli. Increases in guard-cell cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)) have been observed in response to stimuli that cause both stomatal opening and closure. In addition, several important components of Ca(2+)-based signalling pathways have been identified in guard cells, including the cADP-ribose and phospholipase C/Ins(1, 4,5)P(3)-mediated Ca(2+)-mobilizing pathways. The central role of stimulus-induced increases in [Ca(2+)](cyt) in guard-cell signal transduction has been clearly demonstrated in experiments examining the effects of modulating increases in [Ca(2+)](cyt) on alterations in guard-cell turgor or the activity of ion channels that act as effectors in the guard-cell turgor response. In addition, the paradox that Ca(2+) is involved in the transduction of signals that result in opposite end responses (stomatal opening and closure) might be accounted for by the generation of stimulus-specific Ca(2+) signatures, such that increases in [Ca(2+)](cyt) exhibit unique spatial and temporal characteristics.
authors.affiliation: Institute of Environmental and Natural Sciences, Department of Biological Sciences, Lancaster University, Lancaster LA1 4YQ, U.K. m.mcainsh@lancaster.ac.uk
authors.forename: M R
authors.initials: MR
authors.lastname: McAinsh
authors.forename: J E
authors.initials: JE
authors.lastname: Gray
authors.forename: A M
authors.initials: AM
authors.lastname: Hetherington
authors.forename: C P
authors.initials: CP
authors.lastname: Leckie
authors.forename: C
authors.initials: C
authors.lastname: Ng
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D036563:Cyclic ADP-Ribose; D004305:Dose-Response Relationship, Drug; D004963:Estrenes / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism*; D018521:Plant Physiological Phenomena; D011760:Pyrrolidinones / Q000494:pharmacology; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D004963:Estrenes; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D036563:Cyclic ADP-Ribose; D000246:Adenosine Diphosphate Ribose; D002118:Calcium