Compartmental Efflux Analysis and Removal of Extracellular Cadmium from Roots

作者：Wilfried E. Rauser · 发表于：PLANT PHYSIOLOGY · 年份：1987 · DOI：10.1104/pp.85.1.62 · 被引用次数：80 · 研究领域：Plant Stress Responses and Tolerance、Plant Genetic and Mutation Studies、Plant tissue culture and regeneration

Profiles of (109)Cd efflux from roots into three solutions were determined for young intact plants of Agrostis gigantea and maize. The solutions were (a) nutrient culture medium containing 3 micromolar Cd at room temperature, (b) ice-cold 5 millimolar CaCl(2), and (c) ice-cold 5 millimolar PbCl(2). Efflux profiles were clearly resolved into three easily discernible components having fast, medium, and slow exchange rates. These results were unexpected for the situation where some intracellular Cd was present both as extractable Cd-binding peptide and in electron-dense granules within the cytoplasm and the vacuoles. Adding a fourth compartment to the curve-fitting model produced a splitting of the fast exchanging component. Use of these efflux kinetics to estimate Cd fluxes through membranes was inappropriate. However, they were useful in determining optimal washing times for the removal of extracellular Cd. A 10 minute wash in ice-cold 5 millimolar CaCl(2) is recommended for this purpose for Agrostis and maize roots.