Variation in Single Spore Cultures of Aspergillus Fischeri

SUMMARY

Using a modified Chambers micromanipulator, 448 single spore cultures were obtained from a stock culture of Aspergillus Fischeri, a perithecial form. Certain of these cultures showed striking morphological variations from the stock culture, and this paper is concerned with a study of the variant cultures.

Variant cultures were of two main types: (1) Very large, scattered perithecia were produced, as opposed to the condition in the stock culture where the perithecia are small, and closely and uniformly distributed. (2) Conidia were produced in profusion, while very few perithecia were formed and those only tardily, contrary to the case in the stock culture.

In the case of a certain culture of type (1), cultures derived from it, both from ascospores and conidia, through several single spore generations reproduced the characters of the variant parent. In another instance, however, single ascospore derivatives through a number of single spore generations produced not variant cultures, but cultures practically identical morphologically with the original stock culture. Cultures derived from conidia, on the other hand, reproduced the variant type. Single spore cultures from a type (2) variant reproduced the variant characters, whether the cultures were derived from single ascospores or single conidia.