SUMMARY: Phormidium persicinum requires light intensities < 300 foot-candles and grows at 10°–33°. The medium developed for P. persicinum is representative of the early types of artificial media having a relatively high concentration of chelator and, necessarily, of trace metals. Other media, varying widely in trace metal: chelator ratios and concentrations allow growth of P. persicinum. Tris 2-amino-2- hydroxymethylpropane-1:3-diol is a suitable pH buffer; its antagonism of potassium utilization was demonstrated and was amply overcome by the addition of 200 mg. K/l. to the medium. Inorganic and organic phosphates were utilized and were required at relatively low concentrations. P. persicinum utilized NO3− and NH4+ but not atmospheric nitrogen. NaNO3 was the most satisfactory inorganic nitrogen source but the cultures bleached after prolonged growth. Asparagine (0·2–0·8 g./l.) maintained the normal purple pigmentation over a longer period; it served as a non-toxic slowly-utilized reservoir of available N. Vitamin B12 is the only essential vitamin and is needed at a concentration (100 mμg./l.) which is higher than for most algae. All the cobalamins including factor B, but not methionine or deoxy- ribosides, can substitute for vitamin B12. The physiological and ecological resemblances of P. persicinum to red or violet blue-green algae growing in deep water are discussed.
ProvasoliL.1957; Growth factors in unicellular marine algae: Scripps Symposium on ‘Perspectives in Marine Biology’
. University of California Press; In the Press
ProvasoliL.,
McLaughlinJ. J. A.,
PintnerI. J.1954; Relative and limiting concentrations of major mineral constituents for the growth of algal flagellates. Trans. N.Y. Acad. Sci 16:412
ProvasoliL.,
PintnerI. J.1954; Cultural characteristics of Phormidium persicinum, an auxotrophic marine red-pigmented blue-green alga. Rapports et Comm, du VIII Congres Inter, de Bot. Sect 17:39
ShiloM.,
ShiloM.1953; Conditions which determine the efficiency of ammonium sulphate in the control of Prymnesiumparvum in fish breeding ponds. Appl. Microbiol 1:330