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

Conference · Wed May 01 04:00:00 EDT 1991 · Plant Physiology, Supplement; (United States)

OSTI ID:5559523

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

---

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--
• Conference Information: Journal Name: Plant Physiology, Supplement; (United States) Journal Volume: 96:1
• Country of Publication: United States
• Language: English

Related Subjects

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