Aug. 1, 1925 
Nitrogen Constituents of Celery Plants 
291 
orated to dryness on the water bath and the acid amide, humin, and 
diamino acid nitrogen estimated according to Ilausmann’s nitrogen 
distribution method. 
Protein nitrogen was determined by Stutzer’s method (21, p, 105; 
22, p. 475). In this method, 1 gm. samples of the dry celery powder 
were treated in the beaker with water (100 c. c.) heated to boiling 
and kept on the water bath for from 10 to 15 minutes. Then 2 c. c. 
of concentrated potassium-alum solution and 15 c. c. (0.45 gm. 
Cu(OH) 2 ) of Stutzer’s solution 3 were added and the mixture stirred 
thoroughly. On cooling, it was filtered and thoroughly washed with 
water. The residue and filter paper was transferred to a Kjeldahl 
flask and the “protein nitrogen” oxidized by the Kjeldahl-Gunning 
method. 
The nitrogen in the filtrate and washings from the Cu(OH) 2 resi¬ 
due was determined by the Kjeldahl-Gunning method and called 
nonprotein nitrogen. The results for the analysis are nearly the 
same as those arrived at by subtracting the figures for protein “N” 
from those for total “N”; they are at least within the error due to 
sampling which must be considered in all the estimations. 
The results of the analyses by the above-described methods are 
given in Tables I and II. 
Table I.— Average 1 nitrogen distribution in healthy celery leaves and in leaves 
affected with u early blight ” (Cercospora apii) 
[Total nitrogen expressed in per cent of oven-dried leaves: Healthy, 4.77 per cent; blighted, 2.94 per cent. 
Nitrogen distribution expressed in per cent of total nitrogen] 
Form of nitrogen 
Blighted 
Healthy 
Nitric nitrogen: 
Scales’s Zn-Cu couple _ _ _____ 
* 5.3 
8.7 
Schulze-Tieman___ ______ 
4.0 
• 6,7 
Ammonia nitrogen_ _ __ __ 
2.6 
1.3 
Nitrogen of nitrites....-____„__ 
(2) 
(») 
Total hydrolyzable nitrogen_________ _ 
88.3 
90.9 
Acid amide nitrogen_________- 
16.5 
16.7 
“Humin” nitrogen_________ 
10.6 
6.5 
Diamino-nitrogen ___ 
15.5 
16.8 
M onoamino nitrogen.., .... 
45.6 
50.7 
Protein nitrogen.....^ ___ 
74.4 
68.3 
Nonprotoin nitrogen........,.. 
25.3 
29,7 
i For data from which these averages are computed see Table II. 
* Strongly positive test. 
* Faint trace. 
METHODS USED WITH CELERY LEAVES ATTACKED BY SEPTORIA APII 
Mature celery leaves of approximately the same age, taken from 
plants of the Easy Bleaching variety grown on muck soil at Kalama¬ 
zoo, Mich., were used. The diseased leaflets used for analysis had 
spots occupying from one-tenth to one-sixth of the leaf area, while 
those called healthy were, apparently free from spot. The samples 
were dried for two days on cheesecloth over a steam radiator (tem¬ 
perature 40° to 50° C.) and then were pulverized and dried further in 
an electric oven held at 50° C. Samples were then sealed in jars. 
* Preparation of Stutzer’s reagent: 100 gm. of CUSO 4 + 5 H 2 O were dissolved in 5 liters of water to which 
2.5 c. c. of glycerol were added and then enough NaOH to render the solution faintly alkaline. The 
precipitate was filtered and washed with water containing 5 c. c. glycerol per liter until free from alkali. 
The precipitate was then taken up with water containing 10 per cent glycerol and the amount of Cu(OH >2 
per c. c. determined by the following method: 2 c. c. of Stutzer's solution were treated with 2.5 c. c. of 
concentrated HNO 3 and 25 c. c. of water and then boiled. Treated with 5 c. c. of bromine water, boiled, 
treated with NH 4 OH, boiled, treated with acetic acid, boiled, cooled, 3 gm. KI added, and titrated with 
Na2S2C>3. 
