Conservation and instability des souches de champignons filamenteux impact de la cryoconservation

Abstract

The analyse of the results obtained by different mandhods is reported here. The processings of preservation may induce some variable destructions according to the age and the strength of the strains. Important destructions may provoque the death of the mycelium. But the landhal effect may be compensed by the number of reviviscent mycelial elements. The physiological state of the treated material is an important element for the survey. It appears today that freeze-drying and cryo- preservation (in liquid nitrogen) correctly performed do not increase the frequence of mutations. They don't stop the variation of the strains as far as it is a matter of dedifferenciation (Trichophyton ru- brum pleomorphism). Cryopreservation seems to be reliable if it is used for elements with high epige- nic stability, as differenciating compartments of mycelium or young conidia. It may induce reversible biochemical variations on mature conidia (Trichoderma viride). Freeze-drying does not. So it appears that, when it is possible (spores with heavy walls or sclerotia) freeze-drying is bandter than cryopreservation. © 1986 Taylor & Francis Group, LLC.