title: Involvement of extracellular calcium influx in the self-incompatibility response of Papaver rhoeas.
abstract: We have previously demonstrated that increases in cytosolic free Ca2+ are triggered by the self-incompatibility (SI) response in incompatible Papaver rhoeas (the field poppy) pollen. However, one key question that has not been answered is whether extracellular Ca2+ may be involved. To address this question, we have used an ion-selective vibrating probe to measure changes in extracellular Ca2+ fluxes around poppy pollen tubes. Our data reveal several findings. First, we confirm that there is an oscillating Ca2+ influx directed at the apex of the pollen tube; we also provide evidence that Ca2+ influx also occurs at the shanks of pollen tubes. Second, upon challenge with self-incompatibility (S) proteins, there is a stimulation of Ca2+ influx along the shank of incompatible pollen tubes, approximately 50 microm behind the pollen tube tip. This demonstration of SI-induced Ca2+ influx suggests a role for influx of extracellular Ca2+ in the SI response.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 TT, UK.
authors.forename: Vernonica E
authors.initials: VE
authors.lastname: Franklin-Tong
authors.forename: Terena L
authors.initials: TL
authors.lastname: Holdaway-Clarke
authors.forename: Kornelis R
authors.initials: KR
authors.lastname: Straatman
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Kunkel
authors.forename: Peter K
authors.initials: PK
authors.lastname: Hepler
mesh_terms: D001692:Biological Transport / Q000502:physiology; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D005298:Fertility / Q000502:physiology; D005682:Gadolinium / Q000494:pharmacology; D017736:Ion-Selective Electrodes; D007811:Lanthanum / Q000494:pharmacology; D010207:Papaver / Q000502:physiology*; D011058:Pollen / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism
chemical_list: D007811:Lanthanum; D005682:Gadolinium; D002118:Calcium