Effects of Fire on the Survival of and Development of Fruiting Bodies of Arbuscular Mycorrhizal Fungi – Final Report

Final report on the project

Mr. Greg Pattinson, Dr. Peter McGee and Ms. Kate Hammill, School Biological Sciences, The University of Sydney.

Post fire survival of seedlings depends on the plant gaining adequate water and mineral nutrients to supplement the limited supply stored in the seed. For many plants with small seeds, the immediate establishment of mycorrhizas on the root system facilitates both. The effect of fire on the survival of arbuscular mycorrhizal fungi and the stimulation of propagule formation was studied. We tried to examine the effect of fire in the field, but were unsuccessful. Mycorrhizal fungi found in the sandy soil of the study area are highly sensitive to disturbance. The collection of soil cores disturbed the hyphal network to an extent where little infection developed, therefore the experiments have had to be conducted in the laboratory.

The components of fire, heat and smoke, were examined separately The surface of soil blocks inoculated with one of three mycorrhizal fungi (Glomus macrocarpum, Glomus isolates NH 1.5 and NH 1.10) were heated, reaching 70ÂșC at 5 cm. The infectivity of the mycorrhizal fungi was drastically reduced in the 13-5 cm layer of soil. There was a moderate decline in the 5-10 cm layer of soil and no observable decline in the 18-15 cm layer of soil. The initiation of infection by mycorrhizal fungi was not affected by the application of “smoky water” to seedlings. The application of “smoky water” and a mulch covering had no affect on the stimulation or total production of sporocarps by the AM fungi.

A publication is currently under preparation and will be submitted to Mycological Research in December 1997.