title: The comparative uptake of Ba2+ and other alkaline earth metals by plant mitochondria.
abstract: (1) The transport of Ba2+ by mung bean (Phaseolus aureus L) mitochondria is examined and its uptake properties compared with the accumulation of other alkaline earth metals by plant mitochondria. Uptake is supported by oxidizable substrates but not by ATP under the conditions examined. Ba2+ uptake shows an absolute requirement for Pi, whereas AsO4, acetate and oxalate do not replace Pi. ATP synthesis inhibits Ba2+ uptake 50% and both 2,4-dinitrophenol and valinomycin plus K+ inhibit uptake over 80%. (2) The relative capacity to transport a series of alkaline earth metals showed a preferred order of: Sr2+ > Ca2+ > Ba2+ >> Mg2+. Mitochondria isolated from three plant sources showed net levels of Mg2+ uptake 7% or less than the observed Sr2+ uptake values. The same relative order of alkaline earth metal supported uptake of Pi was observed with bean (Phaseolus vulgaris L) mitochondria. It is suggested that salt transport in plant mitochondria involves a carrier complex which binds both divalent cations and Pi.
authors.affiliation: The Department of Botany, The University of Texas, Austin, Texas 78712, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Wilson
authors.forename: G A
authors.initials: GA
authors.lastname: Minton
mesh_terms: D019297:2,4-Dinitrophenol / Q000378:metabolism; D019342:Acetic Acid / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001152:Arsenicals / Q000378:metabolism; D001464:Barium / Q000378:metabolism*; D002412:Cations / Q000378:metabolism; D019069:Cell Respiration / Q000502:physiology; D007476:Ionophores / Q000378:metabolism; D008673:Metals, Alkaline Earth / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D019815:Oxalic Acid / Q000378:metabolism; D010084:Oxidation-Reduction; D027805:Phaseolus / Q000166:cytology / Q000378:metabolism*; D014475:Uncoupling Agents / Q000378:metabolism; D014634:Valinomycin / Q000378:metabolism
chemical_list: D001152:Arsenicals; D002412:Cations; D007476:Ionophores; D008673:Metals, Alkaline Earth; D014475:Uncoupling Agents; D014634:Valinomycin; D001464:Barium; D000255:Adenosine Triphosphate; D019815:Oxalic Acid; D019297:2,4-Dinitrophenol; D019342:Acetic Acid