Mar. io, 1923 Aluminum and Iron Compounds in Corn Plants 
805 
interest also is the fact developed by Conner (6) that the quantities of 
soluble iron in soils are greater when the soils are saturated. 
Spurway (23) presents data relative to the influence of various salts 
on the release of soluble aluminum compounds in four soils which he 
studied. The general tendency of all of the treatments of these soils 
was to increase the quantities of soluble aluminum, the greatest effect 
being produced by calcium carbonate and acid phosphate. He reports 
also that hydrated lime increased the amount of aluminum in the first 
leaching, but a marked decrease occurred in the second leaching, 15 
days after the treatment. 
It is evident that the importance of available aluminum salts in the 
soil is beginning to be appreciated. Aluminum is found in practically 
all the soils in the Com Belt, and it is certain, therefore, to become an 
increasingly important factor in soil management when a system is 
practiced which does not conserve the calcium and phosphorus salts. 
DISTRIBUTION OF IRON AND ALUMINUM IN NORMAL AND DISEASED 
PLANTS 
The tissues in which the metals, iron and aluminum, accumulate are 
the vascular plate tissues in the nodes of the stalk and shanks and the 
scutellum of the kernels, as shown in Plate 5. The metals also concen¬ 
trate in the leaf tissues, as has been determined repeatedly by quanti¬ 
tative analyses. As a rule, the oldest leaves contain the largest quan¬ 
tities of these metals. Gile and Carrero (9) have shown that iron is 
immobile in the oldest rice leaves and in this respect is similar to silicon 
and magnesium. 
The locations of the tissues in the stalk in which iron and aluminum 
accumulate are those referred to as “zone B” in Plate 3, A. These 
tissues appear white in normal stalks, with traces of yellow and some¬ 
times green. When the metals concentrate in them they show various 
gradations of color and of disintegration. Plates 2, B; 5, A and B; 
and 6 show different kinds of injuries observed in plants in the field. 
The extreme toxicity of copper sulphate is seen in Plate 3, B, where 
the tissues in both zone A and zone B have been seriously affected. 
This is the only metallic salt studied so far which affects both zone A and 
zone B tissues. The tissues of the basal nodes, shown in Plate 7, B, are 
the tissues in which the accumulations occur first. They are the oldest 
functioning nodal tissues, and their length of service, as indicated by a 
continued healthy appearance of the roots which have their origin in 
these tissues, seems to be related to the relative quantities of iron and 
aluminum which accumulate in them. Part of the basal tissues in the 
stalk shown in Plate 8, B, are not functioning, as shown by the dry 
appearance of the lowest and oldest roots. The plant was able, how¬ 
ever, to produce additional roots and thereby continue vegetative growth. 
In Plate 7, A and B, is shown the base of a stalk which manifested 
disease symptoms and which was barren. The basal tissues contained 
abundant accumulations of iron and aluminum compounds. Instead 
of the metals being distributed more or less uniformly throughout the 
stalk, as in the normal plant shown in Plate 9, the largest quantities 
were present in the lower nodal plates and these were brownish purple 
discolored, and disintegrated, as shown in Plate 7, C. 
