Apr. 16,1917 
Absorption of Nutrients 
79 
roots in the nitrogen-free solution and one-fourth in the complete 
solution. 
The nutrient solutions used were the same as those in Experiments I 
and II. The no-nitrogen plants were grown 30 days in 200-c. c. flasks; 
all others, 27 days in 200-c. c. flasks and 13 days in 500-c. c. flasks. Six 
flasks were taken as a unit and the units triplicated for each treatment. 
Solutions were changed eight times during the experiment. Experi¬ 
mental data are given in Tables VIII and IX. 
Table VIII .—Growth of rice in Experiment IV 
Nutrient solution. 
Weight of stalks 
and leaves. 
Number of 
roots. 
Average oven- 
dry weight 
of roots. 
A-flasks. 
B-flasks. 
Flask 
No. 
Green. 
Oven- 
dry. 
Av¬ 
erage A- 
oven- flasks. 
B- A- 
flasks. flasks. 
B- 
flasks. 
Ratio 
of 
roots 
to 
tops. 
dry. 
Nitrogen-free 
Do. 
Complete 
Nitrogen-free, 
Complete.. . . 
_do.. 
[1-6 
7-12 
I13-18 
[19-24 
25-30 
[31-36 
[37-42 
43-48 
149-54 
Gm. 
1.50 
1.47 
1.49 
53-n 
47-15 
53-92 
85. 70 
84.83 
85-66 
Gm. 
o. 36 
•37 
.38 
8.44 
7-63 
8.83 
12.27 
12- 4X 
12. 55 
Gm . 
• 0.37 
• 8.30 
•12.41 
54 
44 
45 
247 
191 
259 
212 
I98 
188 
55 
43 
58 
75 
80 
72 
187 
207 
212 
Gm. 
* o. 148 
•2. 732 
►2.103 
Gm. 
o. 147 
1.025 
2.132 
o, 797 
•453 
•34i 
Table IX .—Nitrogen and phosphoric acid absorbed by rice in Experiment IV 
Flask No. 
Nitrogen 
(N) in dry 
stalks and 
leaves. 
Nitrogen (N) in dry 
roots. 
Nitrogen 
(N) ab- j 
sorbed by j 
12 plants. 
1 Nitrogen 
(N) ab- 
! sorbed per 
gram of 
roots. 
Phospho¬ 
ric acid 
(P3O5) in 
dry stalks 
and 
leaves. 
A-flasks. 
B-fiasks. 
I-18 
19-36 
37-54 
Per cent. 
i- 33 
3 - 72 
4- 63 
Per cent. 
. O. 50 
i -37 
2. 47 
Per cent. 
O. 50 
2.38 
2.47 
Gm. 
Gm. 
Per cent. 
0. 3642 
. 6666 
°-355 
• 157 
I. 60 
1. 60 
If we assume that plants 37 to 54 were normal in growth and compo¬ 
sition, it appears that plants 19 to 36, with one-fourth of their roots in 
the complete solution, made about two-thirds the normal growth, had 
a 33 per cent higher ratio of roots to tops, absorbed 0.55 of the normal 
amount of nitrogen, and, per gram of roots, absorbed 2.26 times the 
normal amount of nitrogen. 
The plants with one-half their roots in the complete solution in Experi¬ 
ments I, II, and III absorbed, respectively, 0.77, 0.76, and 0.74 as much 
nitrogen as the normal plants, and absorbed, respectively, 1.45, 1.48, 
and 1.45 times as much nitrogen per gram of roots as the normal plants. 
A comparison of the results of Experiments I, II, and III with those of 
this experiment shows that the smaller the portion of roots supplied with 
nitrogen, the less nearly the plants reach the maximum absorption of 
