Factors affecting vegetative growth and the production of perithecia in culture by Ophiobolus graminis. II. Variations in light and temperature

Abstract

Sixty-one isolates of O. graminis were shown to be obligate photosporulators. Fertile perithecia developed only when the cultures were exposed to light of between 65 and 360 f.c., with a maximum at 200 f.c. The temperature range for the production of fertile perithecia was between 13 and 24°c, with the optimum at 20°.

Studies on the interaction of light and temperature showed that when cultures received sufficient light, temperature controlled perithecial numbers.

Light most effective in photosporulation was of wavelengths between 390 and 450 mμ. Red light neither inhibited nor stimulated reproduction. At least 12 hr of illumination was required, and perithecial numbers per unit area increased with increasing light period until the cultures dried out.