NITROGEN UTILIZATION IN 38 FRESHWATER CHLAMYDOMONAD ALGAE

Abstract

Axenic cultures of 38 organisms, half of these available from culture collections of algae and half newly isolated, were investigated for nitrogen utilization. When NaNO₃, NaNO₂, (NH₄)₂SO₄, and NH₄NO₃ were used as sole sources of nitrogen in an organic basal medium, it was evident that most of the organisms used NaNO₃ and NaNO₂ with equal facility. (NH₄)₂SO₄ was utilized to about the same extent as NH₄NO₃, and both were used with less facility than NaNO₃ and NaNO₂. Growth in the basal medium with any of nine amino acids as sole nitrogen sources (namely, asparagine, ornithine, aspartic acid, lysine, serine, glycine, glutamic acid, alanine, and glutamine) was sufficiently differential to suggest possible taxonomic utility. When study was made of certain nitrogenous bases as sole nitrogen sources, it was found that adenine and uric acid were widely utilized, but cytosine, thymine, and uracil supported little or no growth. Again, when acetamide and succinamide were used as sole sources of nitrogen, and growth was compared with that in media containing glutamine and asparagine, patterns of growth differed from organism to organism. In summary, it can be said that these experiments provide data on growth patterns which may be significant as supplements to strictly morphological attributes of the organisms.