Response of tonoplast H sup + -pump and ATPase to cadmium

Conference · Wed May 01 00:00:00 EDT 1991 · Plant Physiology, Supplement; (United States)

OSTI ID:5559523

Salt, D E; Wang, Lin; Wagner, G J ^[1]

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1. Univ. of Kentucky, Lexington (United States)

It has been demonstrated that Cd{sup 2+} accumulates in vacuoles of tobacco leaves exposed to 20 {mu}M Cd{sup 2+}, after 4 days of growth in Hoaglands medium. The accumulation of Cd{sup 2+} is also associated with the accumulation of Cd{sup 2+}-peptide (phytocelatin) in the vacuole. The transport of Cd{sup 2+} and/or Cd{sup 2+}-peptide across the tonoplast membrane may be energized by the H{sup +} electrochemical gradient that exists across this membrane and which is generated by an H{sup +}-pumping ATPase. In vitro 2 {mu}M Cd{sup 2+} inhibits oat root tonoplast H{sup +}-pumping ATPase by 50% with a Ki of approximately 4.0 {mu}M. However, exposure to 2- {mu}M Cd{sup 2+} for 4 days during germination and growth of oat seedlings causes a 100% increase in tonoplast H{sup +}-pumping ATPase activity. This increase on exposure to Cd{sup 2+} during growth may represent part of the physiological mechanism whereby plants accumulate Cd{sup 2+} and/or Cd{sup 2+}-peptide within the vacuole. This could also represent an acclimation of H{sup +}-pumping activity to Cd{sup 2+}. Current studies are testing the effects of Cd{sup 2+}-peptide, organic acids and other ligands on H{sup +}-pumping activity and Cd{sup 2+} transport in root derived tonoplast vesicles of oat and tobacco.

• OSTI ID: 5559523
• Report Number(s): CONF-9107184-; CODEN: PPYSA
• Journal Information: Plant Physiology, Supplement; (United States), Vol. 96:1; Conference: Annual meeting of the American Society of Plant Physiology, Albuquerque, NM (United States), 28 Jul - 1 Aug 1991; ISSN 0079-2241
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CADMIUM
TOXICITY
ATP-ASE
BIOLOGICAL ACCUMULATION
BIOLOGICAL ADAPTATION
CADMIUM COMPOUNDS
CATIONS
LEAVES
NICOTIANA
OATS
PEPTIDES
PHYSIOLOGY
PLANT GROWTH
PROTON TRANSPORT
ROOTS
SEEDLINGS
ACID ANHYDRASES
CEREALS
CHARGED PARTICLES
CHARGED-PARTICLE TRANSPORT
ELEMENTS
ENZYMES
GRAMINEAE
GROWTH
HYDROLASES
IONS
LILIOPSIDA
MAGNOLIOPHYTA
MAGNOLIOPSIDA
METALS
ORGANIC COMPOUNDS
PHOSPHOHYDROLASES
PLANTS
PROTEINS
RADIATION TRANSPORT
560300* - Chemicals Metabolism & Toxicology