Influence of the external pH on cell growth and silicon metabolism in <i>T. weissflogii</i>.

<p>(<b>A</b>) Variations of the maximal growth rate (μmax) at different environmental pH values. Boxplots correspond to 5 to 11 independent experiments. The highest growth rate at pH = 7.8 was confirmed in individual experiments, but was only significant as compared to pH = 6.4, 6.8 and 8.5 (<i>p</i>≤0.007). (<b>B</b>) Intracellular silicic acid (Sii) content per cell was determined from cells grown in artificial sea medium adjusted to different pH values. (<b>C</b>) Frustule-bound BSi content per cell. Boxpolts in <b>B</b> and <b>C</b> correspond to 4 to 10 independent experiments, with duplicate measurements for each experiment. (<b>D</b>) Boxplot illustrating the silicon incorporation rate, <i>i.e.</i>, the rate of frustule formation (pmol cell⁻¹ μ^−D) as a function of environmental pH. For explanations about boxplot representation, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0046722#s2" target="_blank">METHODS</a>.