The Uptake of 63Ni by the Diatom Phaeodactylum tricornutum

Kinetic studies of the uptake of 63Ni by cultures of the diatom Phaeodactylum tricornutum Bohlin revealed that the uptake capacity of the cells depended strongly on their metabolic state. Phosphate‐starved cells gave saturation‐type uptake curves and had low nickel‐binding capacity. This was increased markedly by the addition of phosphate to the cultures. When nickel ions were added before or together with the phosphate, the increase in nickel‐binding capacity of phosphate‐starved cells failed to appear more or less completely. Uptake of phosphate and formation of polyphosphate by the cells were not affected by the addition of nickel to the growth medium. The phosphate dependent synthesis of the principle involved in nickel binding was induced 15–20 h after the addition of phosphate to starved cells. Whether phosphate was directly or indirectly involved in this process could not be established.