Figure 1.

The growth of Chlamydomonas CC-4532 in response to iron supplementation depends on the carbon source. Cells were cultured in TAP for photoheterotrophic growth (acetate) or TP for photoautotrophic growth (CO₂) using the revised trace metal supplement (Kropat et al., 2011) at 24°C and shaken at 180 rpm under continuous illumination of 70–80 μmol/m²s, and bubbled with sterile air. (A) Determination of chlorophyll content and (B) maximum quantum efficiency of photosystem II (F_v/F_m). Aliquots of cells grown photoheterotrophic (dark gray) and photoautotrophic (light gray) were removed from the culture during the logarithmic growth phase (~4 × 10⁶ cells/ml). (C) Photoheterotrophically and (D) photoautotrophically grown cells at 0.25 μM (open circles), 1 μM (filled circles), 20 μM (filled inverted triangles) and 200 μM Fe (filled inverted triangles) were counted with a hemocytomer for estimation of growth rates.