Palmelloid Formation of Chlamydomonas

Organic acids such as citrate, oxalate, succinate, fumarate, malate, glutamate, aspartate, glycolate and phthalate induce palmelloid formation at neutral pH in liquid cultures of Chlamydomonas, while acetate hardly does it. The palmelloids consist of a minimum of four cells and are embedded in a jelly‐like material. The effective organic acids are generally not only unutilizable as respiratory substrates, but affect also slightly the respiration or photosynthesis and tend to inhibit growth. In a synchronous culture, an addition of citrate at an early stage of a light or dark period has little or no effect on cell growth and multiplication but inhibits the dissociation of divided daughter cells strikingly.