GROWTH AND SEXUAL REPRODUCTION OF APHANOMYCES EUTEICHES AS AFFECTED BY THE OXIDATION STATE OF SULFUR

Davey , C. B., and G. C. Papavizas . (Crops Res. Div., ARS, USDA, Beltsville, Md.) Growth and sexual reproduction of Aphanomyces euteiches as affected by the oxidation state of sulfur. Amer. Jour. Bot. 49(4): 400–404. Illus. 1962.—Growth and sexual reproduction of Aphanomyces euteiches Drechs., as affected by the oxidation state of sulfur (S), were studied in synthetic media containing d -glucose, dl -glutamic acid, mineral salts phosphate buffer, and various S sources. Organic and inorganic S sources representing some oxidation numbers (valences) were added to the media at concentrations to provide a range from 0 to 128 mg S/liter. The initial reaction in both liquid and solid media was adjusted to pH 6.2. Liquid cultures were maintained at that pH by periodic adjustment. Oxidized S with oxidation number +6 or +4 was not utilized by the fungus, whereas good growth was obtained in the presence of S with oxidation numbers of 0 or -2. Although differences existed among isolates as to relative rates of utilization of the various S sources, there was complete conformity among isolates as to which sources were utilized for growth. Some isolates did not utilize all available S sources for sexual reproduction.