H.V. Leland J.S. Kuwabara 1986 <div class="abstract-group"><div class="article-section__content en main"><p><i>Selenastrum capricornutum</i><span>&nbsp;</span>Printz, growing in a chemically defined medium, was used as a model for studying adaptation of algae to a toxic metal (copper) ion. Cells exhibited lag‐phase adaptation to 0.8 μM total Cu (10⁻¹²<span>&nbsp;</span>M free ion concentration) after 20 generations of Cu exposure.<span>&nbsp;</span><i>Selenastrum</i><span>&nbsp;</span>adapted to the same concentration when Cu was gradually introduced over an 8‐h period using a specially designed apparatus that provided a transient increase in exposure concentration. Cu adaptation was not attributable to media conditioning by algal exudates. Duration of lag phase was a more sensitive index of copper toxicity to<span>&nbsp;</span><i>Selenastrum</i><span>&nbsp;</span>that was growth rate or stationary‐phase cell density under the experimental conditions used. Chemical speciation of the Cu dosing solution influenced the duration of lag phase even when media formulations were identical after dosing.<span>&nbsp;</span><i>Selenastrum</i><span>&nbsp;</span>initially exposed to Cu in a CuCl₂<span>&nbsp;</span>injection solution exhibited a lag phase of 3.9 d, but this was reduced to 1.5 d when a CuEDTA solution was used to achieve the same total Cu and EDTA concentrations. Physical and chemical processes that accelerated the rate of increase in cupric ion concentration generally increased the duration of lag phase.</p></div></div> application/pdf 10.1002/etc.5620050211 en Wiley Adaptation of Selenastrum capricornutum (Chlorophyceae) to copper article