Endophyte-host associations in grasses. XXI. Studies on the structure and development of Balansia obtecta

Abstract

Studies on the structure and development of Balansia obtecta (Ascomycotina, Clavicipitaceae) were conducted. Plants and sclerotia were collected at several sites in Florida. Sections of sclerotia were made and examined using light microscopy. Sclerotia were seen to be composed of both grass and fungal tissues. Sclerotia were germinated in moisture chambers. Two types of gametangial fructifications (spermogonia and ascogonia) were observed. Spermogonia were cupulate and produced masses of moist spermatia. Ascogonia were pulvinate and were composed of aggregations of radiating hypha-like trichogynes. Both types of gametangia were produced on most sclerotia. Crossing studies were conducted and a mating system involving heterothallism was demonstrated. Ascomata developed only after spermatia were transferred to an ascogonium of a compatible mating type. An ascoma consisted of a stipe and a globose stromal head in which numerous perithecia developed.

Key Words:

• Ascomycetes
• Balansia
• grass endophytes
• sexual system