686 
Journal of Agricult ural Research 
Vol. XXVIII, No. 7 
Fig. 2—Relation of temperature to growth of Fusarium cepae on potato agar plates 
RELATION OF ACIDITY AND ALKALINITY 
In order to study the reaction of the fungus to various concentrations of H 
and OH ions the methods outlined by Karrer and Webb ( 5 ) were followed with 
slight modifications. Erlenmeyer flasks of 150 cc. capacity containing 50 cc. 
each of Richard’s solution adjusted to various Ph values were inoculated with 
equivalent amounts of a spore suspension of the fungus. After 10 days’ in¬ 
cubation at 22° C. the mycelial mats were filtered on weighed filter paper,£dried 
at 90° C. and the weight determined. The P H values of the solutions at the 
beginning of the experiment and after removal of the mycelium were determined. 
These with the dry weights of the mycelium are given in Table I. 
Table I .—Growth of Fusarium cepae in Richard’s solution adjusted to various 
Ph values after 10 days at 82° C. 
Ph value 
Dry 
weight of 
mycelium 
At 
beginning 
of experi¬ 
ment 
After re¬ 
moval of 
mycelial 
mat 
1.8 
1.8 
Qrams 
No growth. 
2.2 
2.2 
0.0050 
2.8 
2.8 
.0256 
2.8 
2.8 
.0240 
5.0 
4.6 
.2262 
6.6 
6.8 
.2340 
7.4 
7.2 
.1845 
8.2 
8.0 
.1460 
8.4 
8.2 
.0209 
9.2 
8.2 
No growth. 
9.6 
8.4 
No growth. 
