title: Stomatal Spacing Safeguards Stomatal Dynamics by Facilitating Guard Cell Ion Transport Independent of the Epidermal Solute Reservoir.
abstract: Stomata enable gaseous exchange between the interior of the leaf and the atmosphere through the stomatal pore. Control of the pore aperture depends on osmotic solute accumulation by, and its loss from the guard cells surrounding the pore. Stomata in most plants are separated by at least one epidermal cell, and this spacing is thought to enhance stomatal function, although there are several genera that exhibit stomata in clusters. We made use of Arabidopsis (Arabidopsis thaliana) stomatal patterning mutants to explore the impact of clustering on guard cell dynamics, gas exchange, and ion transport of guard cells. These studies showed that stomatal clustering in the Arabidopsis too many mouths (tmm1) mutant suppressed stomatal movements and affected CO2 assimilation and transpiration differentially between dark and light conditions and were associated with alterations in K(+) channel gating. These changes were consistent with the impaired dynamics of tmm1 stomata and were accompanied by a reduced accumulation of K(+) ions in the guard cells. Our findings underline the significance of spacing for stomatal dynamics. While stomatal spacing may be important as a reservoir for K(+) and other ions to facilitate stomatal movements, the effects on channel gating, and by inference on K(+) accumulation, cannot be explained on the basis of a reduced number of epidermal cells facilitating ion supply to the guard cells.
authors.affiliation: Institute of Molecular Plant Science, School of Biology, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (M.P.); andLaboratory of Plant Physiology and Biophysics, Institute of Molecular, Cell, and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom (M.P., A.A., M.R.B.).
authors.forename: Maria
authors.initials: M
authors.lastname: Papanatsiou
authors.affiliation: Institute of Molecular Plant Science, School of Biology, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (M.P.); andLaboratory of Plant Physiology and Biophysics, Institute of Molecular, Cell, and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom (M.P., A.A., M.R.B.).
authors.forename: Anna
authors.initials: A
authors.lastname: Amtmann
authors.affiliation: Institute of Molecular Plant Science, School of Biology, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom (M.P.); andLaboratory of Plant Physiology and Biophysics, Institute of Molecular, Cell, and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom (M.P., A.A., M.R.B.) michael.blatt@glasgow.ac.uk.
authors.forename: Michael R
authors.identifier: 0000-0003-1361-4645
authors.initials: MR
authors.lastname: Blatt
mesh_terms: D000465:Algorithms; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017136:Ion Transport; D008954:Models, Biological; D009154:Mutation; D019441:Plant Epidermis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D054046:Plant Stomata / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018526:Plant Transpiration / Q000235:genetics / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014867:Water / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C584663:GORK protein, Arabidopsis; C501210:KAT1 protein, Arabidopsis; C428126:KAT2 protein, Arabidopsis; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D024642:Potassium Channels, Voltage-Gated; D014867:Water; D002245:Carbon Dioxide; D011188:Potassium