Fungi of a Long Island Oak-Birch Forest II. Population Dynamics and Hydrolase Patterns for the Soil Penicillia

ABSTRACT

The penicillia in the A-horizon of a Long Island oak-birch forest form a natural association or taxocene of 32 species studied over a 15 month period by dilution plate analysis. The co-dominants, Penicillium daleae and P. bilaii, were of singular importance since together they accounted for over 80% of the 35,560 isolates. Computation of per cent coverage revealed that 99.98% of the Penicillium taxa occurring in this soil horizon were isolated during the investigation. The use of large numbers of samples did not alter the conclusions drawn about the organization of the taxocene derived from analysis of a limited number of samples collected during a single month. Composition changed since repeated sampling increased the total number of species recorded. The penicillia increased approximately 6-fold in the early spring and then decreased to an essentially constant level during summer, fall, and winter. Twenty-nine Penicillium species as well as certain other fungi were tested for their ability to hydrolyze 14 substrates with glycosidic, ester, and peptide linkages. The penicillia as a group and P. waksmanii and P. fellutanum? were the most active; the Mucorales and P. raistrickii the least. There was no correlation between the number of substrates degraded and the numerical position of an organism in the taxocene.

Key Words:

• coverage
• hydrolases
• Penicillium taxocene
• seasonality
• soil penicillia