. Cronartium comandrae in the Rocky Mountain States. Cronartium comandrae Rocky Mountains Region; Fungi Rocky Mountains Region. 0 10 20 30 40 50 60 70 TIME IN HOURS Figure 8.~Germination response of teliospores to several temperatures. Each curve rep- resents the cumulative mean from 10 Figure unit that automatically rotates cover of large petri plate. When telia are attached to the cover, basidio- spores are cast onto the stationary bot- tom of the petri plate so as to reveal by their position when casting occurred. Effects of Freezing and Heating on Viability The effec
. Cronartium comandrae in the Rocky Mountain States. Cronartium comandrae Rocky Mountains Region; Fungi Rocky Mountains Region. 0 10 20 30 40 50 60 70 TIME IN HOURS Figure 8.~Germination response of teliospores to several temperatures. Each curve rep- resents the cumulative mean from 10 Figure unit that automatically rotates cover of large petri plate. When telia are attached to the cover, basidio- spores are cast onto the stationary bot- tom of the petri plate so as to reveal by their position when casting occurred. Effects of Freezing and Heating on Viability The effect of freezing temperatures on via- bility of teliospores was tested under laboratory con- ditions. Fresh telia produced from greenhouse inocu- lations were excised from comandra leaves. These telia were then subjected to below-freezing temper- atures such as occur during mild to severe frosts in the field (table 5). Each treatment was replicated with nine teUa of equal size for each temperature. A'fter exposure, telia were incubated at 18° C. for 72 hours in moist chambers and basidiospores cast were counted. As shown in table 5, freezing reduces the ability of telia to cast basidiospores. This effect occurred whether or not the process of germination had already begun at the time of freezing; basidio- spore casts were suppressed in telia frozen immedi- ately after removal from comandra leaves and also in telia previously incubated under conditions favorable for germination. Suppression increased with increas- ing severity of freezing treatment. Fresh C. comandrae telia from Cache National Forest were also subjected to warm temper- atures to determine if heat might suppress subsequent casting of basidiospores as it has been shown to do in C. ribicola (Van Arsdel et al. 1956). All telia in each trial were of nearly equal size, and no previous germi- nation had occurred. Five telia were used for each treatment. Both dry teUa (placed in paper bags) and telia in moist chambers wer
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