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Abstract
Atomic absorption spectrophotometry was used to characterize aluminium uptake by the cyanobacterium Anabaena cylindrica. An EDTA-washing procedure was used to distinguish between adsorbed and intracellular aluminium. The intracellular aluminium content increased with increasing external concentration and time. The phosphorus concentration in the growth medium did not affect the rate of aluminium uptake nor did dark treatment or addition of CCCP, an uncoupler of phosphorylation. We therefore conclude that aluminium toxicity is due to intracellular aluminium rather than to interactions with nutrients in the growth medium and that aluminium uptake is independent of phosphorus uptake. The accumulation of aluminium in polyphosphate granules and cell walls of phosphorus-rich cells noted earlier is rather due to an increased binding capacity in these cellular compartments. Also, the rapid uptake of aluminium by A. cylindrica mainly occurs via passive diffusion.
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