Substitution of the Radiation Requirement for Sporulation by Host Tissue in Dendrophoma Obscurans

SUMMARY

Cultures of Dendrophoma obscurans growing on a 10–2 glucose-casein hydrolysate medium required radiation for sporulation. When leaf discs from host tissue or certain plants, particularly members of the Rosaceae, were added to the basal medium, sporulation occurred abundantly in darkness on the leaf surface. The ability to replace the radiation requirement for sporulation did not occur with all plant tissue tested. The active substance in powdered host tissue could be extracted with certain organic solvents but not with water. This crude extract could be concentrated, autoclaved, and when added to the basal medium supported sporulation in darkness.