Mar. 15, 1924 
Elemental Composition of the Corn Plant 
849 
In Table IV the composition of the five root systems is expressed in 
the same manner. The data in Table III shows a striking uniformity in 
the elemental composition, expressed in percentage of dry weight, of the 
leaves, stem and grain of each of the five plants analyzed. The only 
marked exceptions in this regard were the rather wide variations in the 
percentages of oxygen and chlorin. This was true, however, only of the 
stems and leaves since the percentages of these two elements in the grain 
were very uniform. The percentages of several of the mineral elements in 
the five root systems showed considerable variation which may have been 
due, in part, to the unequal distribution of minute particles of soil adher¬ 
ing to or embedded in the exterior tissue of the roots. 
Although the percentage elemental composition is uniform in a like 
organ of the different plants, the actual amount of a given element 
expressed in grams varies considerably, as shown in the latter part of 
Table III. This is due to the fact that plants which are grown under 
the same conditions in the field and which seem to be uniform in size and 
general appearance show marked variations in dry weight and in the 
distribution of this matter in the various organs of the plants. 
DISTRIBUTION OF THE ELEMENTS IN THE ORGANS OF THE PLANT 
The total dry weight of the leaves, stem, grain and cobs of each of the 
five corn plants analyzed was 776.3, 791.1, 659.5, 745-8 and 899.3 
respectively. The average amount of dry matter in the aerial parts of 
the plants was thus 774.4 gm., of which 30.2 per cent was in the leaves, 
26 per cent in the stem, 33.7 per cent in the grain and 10.1 per cent in 
the cob. This proportion of dry matter in the various organs corre¬ 
sponds closely to the observations of Smith ( 11 ) on corn grown in Michi¬ 
gan. He found that 22 per cent of the dry matter of the plant above 
ground was in the leaves, 32 per cent in the stalks and 46 per cent in the 
ears. Table IV shows that the dry weight of each of the five root systems 
isolated was, respectively, 59.5, 62.4, 60.7, 53.9, and 66.0 gm., with an 
average weight of 60.5 gm. The weight of the dry matter of the roots 
was thus 7.81 per cent of the dry weight of the leaves, stem and ear. 
The weight of the roots obtained in this experiment is in accord with 
unpublished data that have been obtained in numerous experiments 
with the corn plant at the Kansas Agricultural Experiment Station. 
These data show that the dry weight of the roots of a mature Freed 
White Dent, Kansas Sunflower, Reid Yellow Dent or Pride of Saline 
corn plant was between 7 and 8 per cent of the dry weight of the portion 
of the plant above ground. 
The values for the weight of the dry matter of the roots of corn are 
much higher than those given by Homberger ( 3 ) and Schweitzer (jo). 
Their results show that the dry weight of the roots of mature com plants 
grown in the field did not exceed 3 per cent of the dry weight of the 
plants. They state, however, that the methods used by them to isolate 
the root systems were unsatisfactory since there was no degree of cer¬ 
tainty that they had obtained all the roots. 
The average percentage composition of the different organs of the 
five plants is shown in die first half of Table V. The average weight 
in grams of the elements that compose, respectively, the stem, leaves, 
grain, cob, and roots is shown in the last half of Table V. These values 
expressed in grams were obtained by multiplying the average weight of 
the organs by their average percentage composition. The total weight 
of each of the elements that make up the mature plant is expressed 
graphically in Figure 1. 
