Lack of mutagenic effects on conidia of Aspergillus amstelodami irradiated by 8.7175-GHz CW microwaves.

Conidial suspensions of Aspergillus amstelodami were exposed to 8.7175-GHz CW microwaves in the near field of a horn antenna. Conidia were irradiated for 3- and 6-hour time intervals and at a temperature ranging between 28 and 30 degrees C. The density of microwave power incident on the suspension was 2.09 mW/cm2. Two types of mutant, conidial colour variants and 8-azaguanine resistant mutants, were looked for. The treatment produced no significant change in the frequencies at which the two classes of mutant were recovered among the survivors as compared with their frequencies from the untreated conidial suspension. Doubling the exposure time did not alter the outcome.