| Popis: |
Hulle cell formation was directly dependent on darkness in strains of Aspergillus versicolor, A. ustus, A. flavipes, and A. niveus. On four different nutrient media hulle cells were observed exclusively or more abundantly in colonies grown in the dark. Aleuriospores in one strain of A. flavipes, although present in colonies cultivated in light, were produced in significantly greater quantities in cultures grown in the dark. Such effects are similar to those in other Aspergillus species where Sclerotium and cleistothecium formation are influenced by dark. Two divergent chains of events seem operative: one, affected by light, is conducive to early differentiation of hyphae and formation of the conidial apparatus; the other, affected by darkness, favours the normal development of mycelium and the successive events which lead to the production of such structures as sclerotia, aleuriospores, hulle cells, and cleistothecia. |
