FACTORS AFFECTING SURVIVAL OF LYOPHILIZED FUNGAL SPORES AND CELLS

Abstract

Spores of Alternaria, Aspergillus, Fusarium, Gliocladium, Penicillium, and Pestalotia, budding vegetative cells of Ustilago, and uredospores of Puccinia graminis, P. helianthi, and Melampsora lini were lyophilized using several techniques and various conditions. The best percentage survival of the lyophilized spores and cells was obtained when the initial freezing of the spore suspensions was just low enough to keep the suspension solid until evaporative freezing conditions were reached. Freezing to very low temperatures was unnecessary. Conditions permitting fast warming of the frozen suspension resulted in increased survival. A preliminary degassing treatment greatly enhanced percentage germination, as did the conditioning of the spores in a moist atmosphere immediately after the opening of the tubes for revival of the organisms.