A Study of Sexuality In Sapromyces Reinschii

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Abstract
SUMMARY Sapromyces Reinschii from several collections was isolated and grown in pure culture on various substrata, the cultural conditions favoring development of mycelia, zoösporangia and sex organs were worked out and the sexuality studied in detail. Thirty-nine pure cultures originating from single zoöspores were raised to mycelial maturity. Of the seventeen isolations studied intensively, four proved to be strongly male, one weakly male, five neuter or neutral, one weakly female and six strongly female. The male strains consistently showed more rapid mycelial growth than the female, this difference in growth rate being greatly accentuated on certain media. When strongly male and strongly female strains were mated the former developed antheridial branches, the latter oögonia, fertilization occurred and normal oöspores developed. Considerable evidence indicated that both the development of antheridial branches on the male and the directional growth of these toward the oögonia were responses to substances diffusing from the female. The female strains consistently showed latent maleness and could develop antheridial branches and even accomplish self fertilization in separate culture. No comparable latent femaleness was observed in the male strains. Since each strain originated from a single uninucleate zoöspore the bisexual potentiality of the females affords strong support to Hartmann's theory of Relative Sexuality. Six possible types of sexuality are postulated for Sapromyces Reinschii, 1, pure male (MM), 2, male with latent femaleness (Mf), 3, neutral, strongly sexed (MF), 4, neutral, weakly sexed (mf), 5, female with latent maleness (mF), 6, pure female (FF). Of these possible types, only three, namely 1, (MM), 4, (mf) and 5, (mF), appear to be represented among the single spore strains investigated in this study.