A QUANTITATIVE ECOLOGICAL STUDY ON THE MONOCENTRIC SOIL CHYTRID, RHIZOPHLYCTIS-ROSEA, IN PROVENCE

Soil samples from six sites in Provence, France, were flooded with wat er and baited with cellophane, specifically to obtain Rhizophlyctis ro sea; all proved positive. By standardizing the cellophane addition and counting the R. rosea thalli that grew on it, derivations of thallus recovery g(-1) of soil (TRG) were possible. Where aliquot soil samples for assay were small, sterilized soil leachate was used to chemically reinforce the flood water. Mean TRG was 395 for a grassland soil and 1293 following drying and removal of small stones from it. Separated l eaf humus from the same dried soil had a mean TRG of 1105. Thought was given to what these figures might represent, in terms of sporangia of R. rosea present in the soil at the time of its collection. These are the first quantitative results in soil ecology for the Chyhidiales.