Growth of Saprolegniaceae in Synthetic Media. I. Inorganic Nutrition

Abstract

An inorganic mineral base was designed, employing ethylenediamine tetracetic acid as metal carrier, which supported heavy growth (on the addition of appropriate organic substrates, DL-methionine, and ammonium) over the range pH 4.5-8.6 and enhanced sporulation of the following spp. of Saprolegniaceae: Achlya bisexualis, A. colorata, A. flagellata, A. klebsiana, A. racemosa, Brevilegnia unisperma, Dictyuchus monosporus, Isoachlya intermedia, Protoachlya paradoxa, Saprolegnia delica, and Thraustotheca primoachlya, Achlya klebsiana did not grow if Mg, Ca, Zn, Mn, Fe, or a S source (DL-methionine) was omitted. The spp. investigated were unable to reduce sulfate. Zoospore production was deficient if concns. of essential metals were below those optimal for growth. Although unknown limiting factors, probably inorganic nutrients, increased the lag phase of growth when the purest available chemicals were used, Cu, Mo, Co, B, and Ga did not appear essential or stimulatory under the conditions of these expts.