Defined Media for Growth and Gamete Production by the Green Alga, Oedogonium cardiacum

Abstract

Defined media consisting of inorganic salts and vitamin B12 are described for tlhe male and female filaments of the green alga, Oedogonium cardiacum. These media provide for a maximal growth rate and for the induction of oogonia and antheridia under the prescribed conditions. The maximal amounts of growth, based on dry weight measurements, compare favorably with other green algae. RESULTSPreliminary experiments used Machlis medium B (5) with Stein's trace elements (7) without the addition of soil extract. As was indicated earlier, this medium would not support the S5S-tained growth of the organism. Replacement of the Stein trace elements with the solution described in Table I resulted in the continuous growth of the organism, but at a very low rate. Experiments were then initiated to improve the growth rate and to control sexuality. In these experiments it was assumed that the optimal levels of the macronutrients were interdependent; thus, all salts were considered as dependent variables.

Gametogenesis, gametes and zygotes: An ecological perspective on sexual reproduction in the algae

“…Davis, Harrison & Dugdale, 1973;French & Hargraves, 1985). In both unicellular and multicellular freshwater algae, nitrogen limitation has frequently been shown to stimulate gametogenesis (Sager & Granick, 1954;Ellis & Machlis, 1968;Hill & Machlis, 1970;Rayburn, 1974;Simona, Van Beem & De Vries, 1984;Hoshaw & McCourt, 1988). Low levels of nitrogen induced gametogenesis in Ulva, whereas high levels induced asexual reproduction (Mohsen et al, 1974).…”

FINE STRUCTURE OF DWARF MALES IN OEDOGONIUM PLUVIALE (CHLOROPHYCEAE)

“…Nannandrous development in dwarf males coming from cultures was observed with the light microscope. Unialgal but not axenic cultures were raised in the Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, from single-filament fragments of androsporophyte and female gametophytes that were grown separately in autoclaved biphasic soil water medium (Machlis 1962, Hill andMachlis 1970). These cultures were kept at room temperature and under a 12:12 h LD light regime provided by coolwhite fluorescent lamps providing 65 mol·m Ϫ2 ·s Ϫ1 .…”

A taxonomic survey ofoedogonium(oedogoniales, chlorophyta) in the South Island and Chatham Islands, New Zealand

“…Reliance on sexual reproduction to avoid unfavourable conditions could have led to the great richness of Oedogonium species. The onset of drying in crude cultures seems to induce fertility in many species, and other authors have found depletion of nutrients (Rawitscher-Kunkel & Machlis 1962), especially nitrate (Hill & Machlis 1970;Machlis et al 1974), to be necessary to stimulate gametogenesis in cultured strains. Raising the free CO 2 level in the induction medium may also be successful for this purpose, though reduction of nutrients may still be necessary (Hoffman 1973b).…”