Untersuchungen �ber die W�rmeaktivierung der Sporangiosporen von Phycomyces blakesleeanus. I

Dormancy, activation and viability of Rhizopus oligosporus sporangiospores

“…Attempts to activate spores by heat treatments at at 50 and 60 °C were unsuccessful. This is in contrast with the very successful activation of Phycomyces blakesleeanus spores after such heat treatment (Halbsguth and Rudolph, 1959). We conclude that heat activation is not suitable for activation of dormant sporangiospores of Rhizopus oligosporus.…”

“…), or light activation (Sussman and Halvorson, 1966;. For example, Phycomyces blakesleeanus spores do not germinate in a suitable culture medium unless they are activated by one of a range of treatments, such as heating for 3 min at 44 °C (Halbsguth and Rudolph, 1959;Van Laere et al, 1980), γ radiation (Van Assche et al, 1977), dithionite treatment (Van Assche et al, 1978), or treatments with acetate, azide and ammonia (Van Laere et al, 1980). Likewise, n-alcohols and high pressure supported the heat activation of P. blakesleeanus (Thevelein et al, 1979) and of Neurospora tetrasperma ascospores (Belmans et al, 1983).…”

Cytological studies on the life-cycle in Absidia glauca Hagem (Mucorales).

“…Germination may occur 6-7 months after onset of dormancy. Sometimes heat-treatment (Halbsguth and Rudolph 1962), NH4-acetate or acetic acid (Delwaux 1973) may break the dorman cy, but we found such treatment not to work in our case. None of the several thou sand examined zygospores developed germ sporangia.…”

Biochemistry of spore germination in Phycomyces

“…A moderate temperature treatment induces reversible activation, i.e., the spores germinate when suspended in culture medium but lose their capacity to germinate when suspended in water [30]. The main factor from the culture medium which keeps the spores activated (and germinating) is glucose [22].…”

“…stockpiled in the spores? The germination of the spores and the concomitant loss of trehalose are also associated with a loss of resistance against several treatments such as heat [30], acids, solvents and heavy metals [15,29]. The spores indeed support desiccation without any loss of viability, and desiccation is a probable event in nature between production and germination of a spore.…”