Variations in the morphology ofChlamydomonas segnishave been investigated under various cultural conditions. In cultures maintained at 250ensp;ft-c and 15 deg;C without aeration, this alga assumed the form of aGloeocystis, whereas in aerated mass-culture grown at 25ndash;30 deg;C and 1000ensp;ft-c the motile stage showed close similarity to the genusGloeomonas. Cells ofC. segnisgrowing in synchronous culture under high light intensity (1000ensp;ft-c) and supplied with 5 CO2in air (v/v) reproduced asexually to form four zoospores, whereas cells provided with air produced only two zoospores. When zoospores developed in light their increase in cell volume was not accompanied by an increase in the length of their flagella. Homothallic anisogamous sexual reproduction could be demonstrated under conditions unfavourable for growth. Ultrathin sections of cells developed in light revealed a lobate, cup-shaped chromatophore. The mitochondria possessed irregular profiles with constrictions and were mainly located on the outer surface of the chloroplast. Intracytoplasmic, convoluted inclusions and interthylakoidal crystals have been observed. Microbody-like organelles, similar to those in plant leaf tissue, occurred in autotrophically grownC. segnis.
展开▼
