Pathology and pathological histology of downy mildew, Sclerophthora macrospora, on six graminicolous hosts.

摘要: At Missouri Agricultural Experiment Station, Columbia, oospores of S. [Sclero-spora] macrospora were found in the tissues a proliferated head Texas Black-hull Kafir sorghum, saved from field at Amherst, Texas, where spikelet abnormalities had been described 1936 (Heredity, 27, pp. 183-194). This appears to be new host record [cf. 35, p. 528; 37, 308]. Detailed examination deformed maize inflorescenes showed intercellular spaces round vascular sheath cells, particularly secondary bundles, primary centres mycelial development, hyphae enlarging form globular, protoplasmic masses, sometimes with thickened walls. Oospores formed association closely appressed xylem cells becoming enlarged and distorted, abnormally pronounced spiral thickening. Irregular thickening leaf husk (to double normal) caused warty appearance. Up 15 sporangio-phores could penetrate through 1 stomata, on either surface. Less extensive studies indicated similar host-parasite relationship wheat, oats, barley, Digitaria sanguinalis.