A Study of Colorado Wheat 
37 
hand, is presumably the end product of the transformations and 
while it may be transferred from one part of the plant to another 
by little-understood processes, it represents the most permanent 
form of nitrogen in the plant. It is, however, evident that the 
total nitrogen includes a very considerable amount of nitrogen in 
other forms; at the end of July only about 60 percent of the total 
nitrogen is present as proteid nitrogen, nitrogen precipitated by 
Stutzer’s reagent, and at the end of the ripening period in a few 
cases as much as 70 percent. The latter figure was obtained in 1915, 
when both the total and proteid nitrogen in the plant were very 
high compared with the results obtained in 1913. 
I have stated that the nitric nitrogen appearing in the wheat 
plant owes its presence to an excessive supply of this form of nitro¬ 
gen in the soil, and is probably accidental. This statement is based 
upon the fact observed in all of the samples examined during the 
two years, i. e., that the plants grown with the application of sodic 
nitrate regularly contain some nitrogen in this form, while those 
grown without it contain either only a very small amount, or no 
nitric nitrogen at all. The table contains only the results of 1915 
and none of those of 1913. At one time we thought that oxidation 
in the air-dried plant actually took place, but were unable to estab¬ 
lish this, and now believe that any nitric nitrogen found, even in 
the dried plant, represents an unused excess originally derived from 
the soil. The method used in determining the nitric nitrogen in the 
plant may give us slightly low results, but it certainly does not give 
us high results, so I think that we can depend upon our results as 
corresponding to the facts, especially as we took 150 grams of the 
green plant, or an equivalent amount of the dried plant, for the de¬ 
terminations. We found no nitric.nitrogen in the heads. The facts 
are, in the mam, concordant with what is known regarding the oc¬ 
currence of nitrates in wheat plants. Jost, in his Plant Physiology, 
p. 140, says “Tobacco, turnips, sunflowers, potatoes and wheat may be 
taken as examples of cultivated plants which contain large quantities of ni¬ 
trates. In the last two the nitrate amounts to from 1.5 to 2.8 percent of the 
dry weight. * * * The maximum of nitrate is found in the root, less in 
the stem and leaf, none at all in the seed. The nitrate increases as the flower¬ 
ing period approaches and decreases when fruiting takes place. * * Such 
storing of nitrate, however, is by no means universal. Many plants absorb 
no more than they absolutely require.” It will be noticed that the 
amounts that we have found in our samples, grown with the applica¬ 
tion of 120 pounds of nitric nitrogen per acre, are far below the 
quantity given by Jost. In summarizing the lecture from which 
the above quotation is taken, Jost says we have learned “that nitric 
acid is the chief source of nitrogen, and that that element in co-operation 
with carbohydrates goes to form proteid especially.” (p. 145). To quote 
Jost again, Plant Physiology, p. 174: “Schultze assumed that the amino- 
acids first arising from the proteid substances, in addition to which perhaps 
