EFFECTS OF TEMPERATURE ON GERMINATION 22$ 



chim roseum, all essentially omnivorous species, germinate very- 

 near the freezing point. In similar studies Ames (1915) employed 

 Glovierella ntfomaculans and Cephalotheciwn roseum from apple, 

 Thielaviopsis paradoxa from pineapple, Fenicillhnn digitatam from 



be 



S 

 c 

 a> 

 v 



- 



C 



o 



-t-> 

 cs 



e 



■ <*-« 



6 



- 



O 



100 



90 



80 



70 



60 



50 



40 



30 



20 



10 

 







8 10 12 14 

 Time (hours) 



16 



18 20 



22 



24 



Fig. 40. Effect of storage indoors for different periods on germination of 

 teliospores of Cronartium ribicola. The curves are based on 3-hour moving 

 averages. Solid line, from teliospores taken from Ribes nigrum and stored 

 for 5 days; dash line, from teliospores taken from R. americanum and 

 stored for 15 days; dot-dash line, from teliospores taken from R. nigrum 

 and stored for 25 days. (After Spaulding and Rathbun-Gravatt.) 



orange, Rhizopus nigricans from sweet potato, and Monilia fruc- 

 ticola from plums and found that near-freezing temperatures 

 must be maintained in storage if germination of these species is 

 to be prevented and development of decay by them entirely 

 avoided. 



The most extensive data on cardinal temperatures among Alyxo- 

 mycetes are those of Smart (1937). He germinated the spores 

 of 70 species, finding that the range 22° to 30° C is optimum for 

 all. At 10° C or lower and above 30° C percentage germination 



