Changes in Atmospheric Spore Content : Diurnal Periodicity and the Effects of Weather

Cambridge

1953

S. 375-393

5 Abb., 1 Taf., 30 Lit. Ang.

Bandaufführung

156277

The use of a power-operated suction trap, in which spores are impacted on the sticky surface of a slowly moving slide, made it possible to estimate accurately the concentration of different kinds of spore in the air at any given time. In an open field at 2 m. above ground the catches often consisted predominantly of small hyaline spores, of types rarely caught by other kinds of trap. Changes in the types of spore caught at different times of day showed that some species have well-defined diurnal periodicity; the catches also reflect changes in weather. In dry weather, pollen grains and spores of such fungi as Cladosporium, Erysiphe, Alternaria, smuts and rusts, are the main components of the air spora; they are most abundant in the afternoon and least in the early morning. Phytophthora infestans and Polythrincium trifolii also occur, but reach their maximum concentration before noon. Prolonged rain removes most of these spores, and for a time there are few in the air. Within a few hours of the start of rain, the typical dry-air spora is replaced by hyaline spores; few of these can be identified, but they include splash-dispersed types, ascospores and basidiospores. Except after rain this damp-air spora occurs in quantity only at night when dew is formed, and the greatest concentration is reached between midnight and dawn. Basidiospores were at times the dominant type of spore. Hyaline forms, often mainly Sporobolomyces sp., rapidly reached large numbers in the early hours of morning, particularly when there was heavy dew, and then disappeared almost completely. Coloured basidiospores mainly from the Agaricales were also commonest at night, but their occurrence depended less on weather than the hyaline forms and their diurnal periodicity was less pronounced.