Morphogenesis and Polymorphism of Ankistrodesmus spp.

Abstract

SUMMARY: Pure cultures of Ankistrodesmus spp. showed continual morphological fluctuation when growing in complex organic media, and to a lesser (though detectable) extent in mineral media. Clonal populations were no less variable. In mineral media, variation of A. braunii was associated with the stationary phase of growth only, but in the complex organic test medium was seen in logarithmic phase as well. The normal processes governing cell morphogenesis are described for A. braunii. Their normal sequence is disrupted by increasing osmotic pressure of the medium in reverse of their normal order in time and of their hypothetical serial coupling to the metabolism concerned with cell growth. The final uncoupling, that of growth from initiation of cell division, is also accomplished by a wide range of C–N heterocyclic ring structures in very low concentration, which may indicate that nucleic acid metabolism is the system concerned at this point in the sequence.