1919] 



WEBB — SPORE GERMINATION AND H ION CONCENTRATION 



215 



Fig. 3. Botrytis cinerea. Graphic representation of the relation of germina- 

 tion to H ion concentration. 



6-hour 



d. Germinat 



27° C. proved very similar 



that at 22° C, except for the fact that the entire cur 

 to have shifted one remove towards the acid side. 

 A series was made up and incubated at 31° C, but 



C 



In no culture was 



This incidental datum is in 



the temperature went as high 



there any sign of germination 



accord with the results obtained by Duggar ('01). He found 



that a temperature of 3^ 



C. was distinctly injurious to spores 

 of Botrytis. Figure 3 exhibits the curves of germination at each 



of the successful temperat 



TABLE IV 



FUSARIUM SP. 



MANNITE 



AVERAGE PERCENTAGES OF SPORE GERMINATION 

 AT DIFFERENT TEMPERATURES AND AT VARIOUS 



HYDROGEN ION CONCENTRATIONS 



IN M/."> 



Temp. Hrs. 



* 



Hydrogen ion concentration, P H 



2.8 



3.1 



4.4 



5.0 



6.2 



7.0 



7.4 



8.8 



9.6 



10.04- 



22° C. 



27° C. 



6 

 20 



6 

 20 



0.0 



57.8 



0.0 



7.9 



0.0 



38.0 



9.7 



65.8 



7.2 

 21.9 



31.0 

 59.6 



9.5 

 20.7 



45.4 

 56.9 



11.6 

 16.0 



18.0 

 33.3 



11.7 



20.1 



23.3 

 39.6 



65.3 

 67.7 



50.0 

 66.3 



21.3 

 36.6 



23.7 

 24.7 



8.5 



27.7 



5.1 

 15.6 



24.6 

 26.9 



0.0 



7.9 



