A physiological comparison of coccolith-forming and naked cells of Coccolithus huxleyi

Summary In a naked clone of the coccolithophorid Coccolithus huxleyi, growth at light saturation was 15% slower than in a coccolith-forming clone isolated from the same parent stock. The two cell types did not differ significantly with regard to cell volume and protein content. A 10–13% smaller chlorophyll a content of the naked cells was matched by a uniform lowering of photosynthetic rates at all light intensities. It was considered that the slower growth of these cells might result from a less favourable ratio between photosynthetic output and biomass.The content of deoxyribonucleic acid was the same in coccolith-forming and naked cells, suggesting that they do not represent different phases in a sexual lifecycle.