title: Characterization of proton extrusion in sunflower cell cultures.
abstract: Cell suspensions derived from callus root tips of sunflower (Helianthus annuus L., cv. enano) were obtained in order to assess the effects of different chemical and physical agents on cell H+ extrusion. Cell H+ efflux was sensitive to temperature, pH, inhibitors of plasmalemma H(+)-ATPase and Ca2+ and K+ concentrations in the assay medium, as well as to the light intensity at which cells were cultivated. Thus, in the darkness and at 60 mumol/m2/s of illumination, a strong inhibition of H+ extrusion was detected as compared to cells grown at 30 mumol/m2/s. H+ extrusion by cells grown at 30 mumol/m2/s was unaffected by the presence of calcium in the assay medium, while at 60 mumol/m2/s such an activity increased when calcium was removed. These results provide the basis for the use of cell suspensions as an appropriate model to investigate the involvement of membrane-associated processes in plant tolerance mechanisms to different environmental stresses.
authors.affiliation: U. E. Bioquímica Vegetal Estación Experimental del Zaidín, C.S.I.C., Granada, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Ferrol
authors.forename: M P
authors.initials: MP
authors.lastname: Rodríguez-Rosales
authors.forename: M
authors.initials: M
authors.lastname: Roldán
authors.forename: A
authors.initials: A
authors.lastname: Belver
authors.forename: J P
authors.initials: JP
authors.lastname: Donaire
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D001593:Benzyl Compounds; D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007701:Kinetin; D008027:Light; D010940:Plant Proteins / Q000378:metabolism*; D010944:Plants / Q000378:metabolism* / Q000528:radiation effects; D011188:Potassium / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011522:Protons; D011687:Purines; D013696:Temperature; D014638:Vanadates / Q000494:pharmacology
chemical_list: D001593:Benzyl Compounds; D010940:Plant Proteins; D011522:Protons; D011687:Purines; D015084:2,4-Dichlorophenoxyacetic Acid; D014638:Vanadates; D004024:Dicyclohexylcarbodiimide; D006180:Proton-Translocating ATPases; D000225:Adenine; C480551:benzylaminopurine; D007701:Kinetin; D011188:Potassium; D002118:Calcium