Kansas Aeromycology XII: Materials, Methods, and General Results of Diurnal Studies 1959–1960

SUMMARY

From October 13, 1959, to November 22, 1960, 18 series of continuous samplings were made (#38–55). Each series was for 24 hours except No. 47 which was for 48 hours. Both silicone slides for fungus spore counts and nutrient plates for identification of colonies were exposed in slit samplers. The culture medium was rose bengal-streptomycin (RBS), and plates were incubated at 23° C for 7 days. Exposures of these materials were made each hour in a slit sampler. A second silicone slide was exposed each hour to test the viability of the spores. These slides were incubated in a moist chamber and the germinating spores were counted directly. The techniques of sampling, counting, and computing data are the same as in previous studies.

A few fungi displayed diurnal periodicity but the majority did not. Basidiospores, one-celled and two-celled hyaline spores, Fusarium colonies, yeasts and hyphal fragments had a nighttime peak, with smuts a light daytime peak. No definite peaks were observed for Cladosporium, Alternaria, Cercospora, and rust. Cladosporium spores and colonies sometimes had peaks during the day, other times at night, but there was no consistent pattern.

Spore viability varied on the average from 42 to 57% with some indication that germination was lowest in the afternoon and highest in the early morning. Maximum germination was October 13, 1960, with 93% at 9 am.