THERMOPHILIC FUNGI - AN ASSESSMENT OF THEIR POTENTIAL FOR GROWTH IN SOIL

An attempt has been made to forecast the potential of thermophilic fun gi to grow in soil in the laboratory and in the field in the presence of a predominantly mesophilic fungal flora at usual temperature. The r espiratory rate of thermophilic fungi was markedly responsive to chang es in temperature, but that of mesophilic fungi was relatively indepen dent of such changes. This suggested that in a thermally fluctuating e nvironment, thermophilic fungi may be at a physiological disadvantage compared to mesophilic fungi. In mixed cultures in soil plates, thermo philic fungi outgrew mesophilic fungi under a fluctuating temperature regime only when the amplitude of the fluctuating temperatures was sma ll and approached their temperature optima for growth. An antibody pro be was used to detect the activity of native or an introduced strain o f a thermophilic fungus, Thermomyces lanuginosus, under field conditio ns. The results suggest that although widespread, thermophilic fungi a re ordinarily not an active component of soil microflora. Their presen ce in soil most likely may be the result of the aerial dissemination o f propagules from composting plant material.