Studies on a species of Monosporascus isolated from triticum

Abstract

A species ofMonosporascus isolated from darkened stem bases ofTriticum in Libya is compared with the two known species of the genus:M. cannonballus andM. eutypoides. The isolate resemblesM. cannonballus in the type of ostiole developed butM. eutypoides in having mainly two-spored asci. It differs fromM. eutypoides in having a reduced ostiole but this may be a response to growth in culture as this species has only previously been reported from infected tissues. In addition to having mainly two-spored and not one-spored asci, the isolate differs fromM. cannonballus in that the spores pass through a stage in which a reticulum is visible when viewed by SEM. SEM photographs of the spores of bothM. cannonballus andM. eutypoides, to which species this fungus is tentatively referred, are included.

On germination the ascospores of theTriticum isolate produce 5–10 germ tubes. A growth curve for cultures is provided showing that the optimum temperature for growth is in the range 25–35°C. Subcultures held at 48° and 55°C for five days failed to grow when transferred to 30°C but ones held at 45° for the same period grew normally when the temperature was reduced to 30°C. The appearance of the colonies at different temperatures is also described.