Salt-stress alters proton transport by the tonoplast ATPase

Conference · Tue May 01 04:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5628437

DuPont, F; Morrissey, P ^[1]

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1. U.S.D.A. Agricultural Research Service, Albany, CA (USA)

A tonoplast-enriched membrane fraction was obtained from roots of barley (Hordeum vulgare cv CM72) seedlings grown in half-strength nutrient solution with or without 100 mM NaCl. Proton transport by the tonoplast ATPase was measured using acridine orange, quinacrine or uptake of ({sup 14}C)-methylamine. The Vmax for proton transport was 2 to 4-fold higher for the ATPase from salt-grown compared to control roots. However, the rate of ATP hydrolysis was not significantly different for the two treatments. The percent inhibition of ATP hydrolysis by DCCD, DIDS and KNO{sub 3} was similar for the two treatments, as was the percent stimulation by Cl. The pH optimum for proton transport was more alkaline for the ATPase from salt-grown roots. No difference was observed between membranes from control and salt-grown roots when oxonol fluorescence was used to measure formation of a membrane potential by the ATPase. Immunoblots of SDS gels were reacted with the antibody to the 68-kD subunit from red beet to assess the relative amount of the 68-kD subunit of the tonoplast ATPase from control or salt-grown roots. The relative amount of the 16-kD DCCD-binding subunit was compared by binding of ({sup 14}C)-DCCD. The amounts of the two subunits were not significantly different in membranes from control or salt-grown roots. The increase in rate of formation of the pH gradient was not accounted for by an increase in the amount of the ATPase.

• OSTI ID: 5628437
• Report Number(s): CONF-9007196--
• Conference Information: Journal Name: Plant Physiology, Supplement; (USA) Journal Volume: 93:1
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ALKALI METAL COMPOUNDS
ATP-ASE
BARLEY
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
CEREALS
CHLORIDES
CHLORINE COMPOUNDS
ENZYMES
GRAMINEAE
HALIDES
HALOGEN COMPOUNDS
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LILIOPSIDA
MAGNOLIOPHYTA
MEMBRANES
PHOSPHOHYDROLASES
PLANTS
ROOTS
SEEDLINGS
SODIUM CHLORIDES
SODIUM COMPOUNDS
TRACER TECHNIQUES