The Effects of Radioactive Substances on Plant Pathogens and Other Microorganisms

摘要

1. Alpha radiation and ultraviolet radiation were used to induce mutants in Phytophthora infestans, Gibberella fujikuroi, Fusarium conglutinans, and Pestalotia sp. The number of mutants produced by-irradiation in these organisms was significantly greater than from natural causes.n2. A minimal medium on which Phytophthora isolate 510 (race 0) would not grow was developed. This medium was used to select irradiated isolates of 510 which would grow on it. Twenty-one such isolates were selected in this manner and tested for pathogenicity.nNo such isolate had pathogenicity increased over the parent, two de¬creased and the other nineteen remained the same.n3. An analysis of the variability in colony growth of isolates of race 0 of Phytophthora infestans indicates that there may be more difference between isolates of the same race than between races in growth rate, depending upon which medium the organisms were grown.