210 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



(Vol. 6 



the solutions as abscissae. Curves corresponding to each of 

 the temperatures of incubation are found in each figure, the solid 

 line representing 22° C, the dotted line, 27° C, and the broken 

 line, 31° C. 



Experimental Data 



In examining the experimental results, it must be borne in mind 

 that perfect germination is not to be expected with these fungi 



the 



In fact 



dextrose would perhaps have vielded 



but it is not certain that it would remain stable with 



the 



given 



work 



desired to employ a full nutrient solution on account of 



difficulties 



H 



adjustmen 



The influence of hydrogen ion concentration upon the germina 



table 



of Aspergillus nvjer may be seen by 



TABLE I 



ASPERGILLUS NIGER. AVERAGE PERCENTAGES OF SPORE 



M/5 MANNITE AT DIFFERENT TEMPERATURES AND 



HYDROGEN ION CONCENTRATIONS 



1 GERMINATION IN 

 i AT VARIOUS 



Temp. 



Hrs. 





Hydrogen ion concentration, 



Pm 







2.8 



3.1 



4.4 



5.0 



6.2 



7.0 



7.4 



2.0 

 14.0 



15.8 



. 

 0.0 



8.8 



9.6 



22° C. 



16 

 26 



38 



33.1 



63.5 

 66.8 



64.2 

 83.1 



87.5 



69.4 



71.8 



33.4 



55 

 55.6 



25 . 9 

 31.0 



1 9 . 8 



42.1 

 42.9 



13.7 

 18.1 

 20 . 2 



9.0 

 13.4 

 15.5 



0.0 



8.2 

 8.6 



0.0 







0.0 



27° C. 



16 

 26 



45 . 3 

 53.0 



20.0 

 23.7 



5.5 

 7.1 



15.1 

 20.1 



0.0 



0.0 



0.0 



0.0 



31° C. 



16 

 26 



22.6 



28.1 



32.6 

 50.4 



46.6 



47.7 



44.0 



45.4 



24.4 

 32.0 



18.6 

 22 . 6 



0.0 

 3.0 



0.0 

 0.0 



0.0 

 0.0 



Incubated at 22° C, the data show that maximum 



hyd 



of P„3.1. 



dro 



there is a marked inhibition of germination, the percentage 



decreasing from 



3.1 to 33.1 at P H 2.8; while, with 



decrease in hydrogen ion concentration from P H 3.1, there is a 



