title: Calcium gradient in plant cells with polarized growth in simulated microgravity.
abstract: Plant cells characterized by apical growth, for example, root hairs and apical cells of moss protonema, are a convenient model to address the problem of gravity response mechanisms including initiation of cell polarity.  The fluorescent calcium probe, chlorotetracycline, allowed us to display the calcium distribution gradient in these cells.  Irradiation by red light led to a sharp decrease in the Ca2+ ion activity in cells.  During clinostatting in darkness the pattern of calcium influx and distribution changes inconsiderably as compared with control; in root hairs calcium is detected mainly in their apices and bases as in control.  Addition of chlorpromazine to the medium probably increases the influx and accumulation of Ca2+ ions.  Under data obtained confirm speculations on the Ca2+ ion functional role for the apical growth of plant cells and may suggest the participation of gravity in redistribution or activation of ion channels, calcium channels included, in the plasmalemma.
authors.affiliation: N.G. Kholodny Institute of Botany, Academy of Science of the Ukrainian SSR, Kiev, USSR.
authors.forename: K M
authors.initials: KM
authors.lastname: Sytnik
authors.forename: O T
authors.initials: OT
authors.lastname: Demkiv
authors.forename: E L
authors.initials: EL
authors.lastname: Kordyum
authors.forename: E M
authors.initials: EM
authors.lastname: Nedukha
authors.forename: L A
authors.initials: LA
authors.lastname: Danevich
mesh_terms: D019068:Bryopsida / Q000737:chemistry / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D016764:Cell Polarity; D002746:Chlorpromazine / Q000494:pharmacology; D018525:Germination / Q000187:drug effects / Q000502:physiology; D006112:Gravitation; D007210:Indoleacetic Acids / Q000494:pharmacology; D008027:Light; D019684:Magnoliopsida / Q000737:chemistry / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D010834:Phytochrome / Q000032:analysis; D010937:Plant Growth Regulators / Q000494:pharmacology; D012399:Rotation; D018474:Weightlessness Simulation
chemical_list: D015220:Calcium Channels; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010834:Phytochrome; D002118:Calcium; D002746:Chlorpromazine