biologia plantarum

Biologia plantarum 5:100, 1963 | DOI: 10.1007/BF02933640

The effect of cytoplasmic factors on the variability ofAspergillus strains

I. Klášterská^1,2

¹ Department of Genetics, Faculty of Natural Science, Charles University, Praha

² Microbiological Institute, Czechoslovak Academy of Sciences, Praha

StrainsAspergillus amstelodami No. 5,A. chevalieri A 24 andA. ruber No. 71 were maintained for 21 generations on wort and on Czapek's medium with 20% sucrose by means of monoconidial isolation. A gradual increase in conidium formation was observed which was different on the two media. No decrease in the formation of perithecia or their disappearance could be observed. In strainsA. amstelodami No. 5 on wort andA. ruber No. 71 on Czapek's medium with sucrose, three morphological changes could be detected, characterized first of all by retarded growth and delayed differentiation during the first days of incubation and by reversibility to the original phenotype in some colonies during subsequent generations.A. chevalieri A 21 displayed two different phenotypic changes on wort medium, the changes appearing to be characteristic and permanent. They are accompanied, in addition to other morphological features, by retarded growth and delayed differentiation during the first days of incubation.
The present results are compared with those ofJinks (1954, 1956) and the origin of the changes observed and the effect of media is discussed. As concerns the reversible changes it can be assumed that they are of extranuclear origin since it appears to be justified to rule out changes caused by the mutation of the genome and by segregation of nuclei due to heterokaryosis. With changes where no reversion can be observed the origin is not clear. Increased sporulation is ascribed to changes in the cytoplasm.

Received: February 14, 1962; Published: June 1, 1963  Show citation