AMERICAN 
JOURNAL OF BOTANY 
Vol. IX February, 1922 No. 2 
THE GROWTH OF FIELD CORN AS AFFECTED BY IRON AND 
ALUMINUM SALTS 
Charles Homer Arndt 
(Received for publication May 17, 1921) 
Introduction 
The investigations of Hoffer and Carr ('20) on corn diseases have shown 
that a brown or brownish-purple discoloration of the lower portion of the 
nodal tissue is frequently associated with evidences of malnutrition and 
of root rot. This discolored area they have designated zone "B." Chem- 
ical analyses showed that a high iron or aluminum content was associated 
with such a discoloration. The injection of iron salts produced a similar 
brownish discoloration, increased the catalase and oxidase activities, and 
reduced the H-ion concentration. Ferrous salts produced these effects 
more readily than did ferric salts. The injection of aluminum salts pro- 
duced no discoloration, but had an effect similar to that of iron salts upon 
the physiological activities. Stalk- and root-rot organisms were usually 
associated with the accumulation of iron and aluminum in zone "B." 
Bordnar ('15) earlier reported a similar correlation between a high aluminum 
content of the sugar beet and its infection by bacterial organisms. His 
analyses showed that a high aluminum content preceded the infection, which 
indicates that an increased aluminum content is in some manner related to 
the decreased resistance to infection. 
The present investigation was undertaken to determine whether toxic 
concentrations of iron and aluminum salts would produce a similar patholog- 
ical condition in corn. With this object in view, a study was made of the 
effect of the composition of the nutrient solution upon the toxicity of 
sulphuric, nitric, and hydrochloric acids and of their corresponding salts 
with iron and aluminum. 
Historical Review 
Some investigators of the toxicity of aluminum salts believed that 
the toxicity is due largely to the acid liberated in the hydrolysis of the 
salts. Abbott, Conner, and Smalley ('13) investigated the effect of alumi- 
num nitrate and nitric acid on field corn. Their results indicated that 
nitric acid is as toxic as the same normality of aluminum nitrate. They 
[The Journal for January (9: 1-46) was issued February 21, 1922.] 
47 
