Kinetics of chromium(V) formation and reduction in fronds of the duckweed Spirodela polyrhiza — a low frequency EPR study
| Autor: | Harold M. Swartz, Klaus-J. Appenroth, Jana Stoeckel, Tadeusz Walczak, Halina Gabryś, Mark Bischoff, Winnefeld K |
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| Rok vydání: | 2000 |
| Předmět: |
Chromium
Chromate conversion coating biology Kinetics Electron Spin Resonance Spectroscopy Analytical chemistry chemistry.chemical_element Plants Low frequency biology.organism_classification Biochemistry law.invention Inorganic Chemistry Spirodela polyrhiza Reaction rate constant chemistry law Atomic absorption spectroscopy Electron paramagnetic resonance Water Pollutants Chemical |
| Zdroj: | Journal of Inorganic Biochemistry. 78:235-242 |
| ISSN: | 0162-0134 |
| Popis: | The uptake of chromate by the duckweed Spirodela polyrhiza was investigated with atomic absorption spectroscopy and the reduction of Cr(VI) to Cr(V) was measured using low frequency EPR spectroscopy. The biphasic kinetics of the uptake was fitted to parameters of a proposed kinetic model. Another model was developed to simulate chromate reduction. The first step of chromate reduction was found to be much faster than the uptake of Cr(VI) from the free space. Most probably, this step occurs already in the cell wall or on the cell membrane surface. Further reduction of Cr(V) to Cr(III) was estimated to be slower. The disappearance of the Cr(V) signal, following transfer of the plants into a Cr-free solution, lasted several tens of hours; the kinetics was mono- or biexponential depending on the length of Cr loading. The rate constants for Cr reduction in living plants were determined for the first time. |
| Databáze: | OpenAIRE |
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