sept. is. is m Acidity of Corn a'nd its Relation to Vegetative Vigor 463 
Table V .-—Comparative acidities of the stalk and leaf juices of vigorous and of stunted 
corn plants , 8 weeks old 
Series IV, vigorous, average height 150 cm., green weight 311 gm.l 
.Series V, stunted, average height 6q cm,, green weight 134 gm. J 
Strain No. 
Stalks. 
Eeavea. 
Titratable 
acidity 
(oc. N/20 
NaOH) 
ol series— 
P»ot 
series— 
Specific 
gravity 
of senes— 
Titratable 
acidity 
(ce. V/ao 
NaOH) 
ofserica—* 
Pa ol 
series—' 
Specific 
gravity 
of series— 
IV 
V 
IV 
V 
IV 
V 
IV 
V 
IV 
V 
IV 
V 
507. 
a-5 
4.8 
5.68 
S’ aa 
1.0183 
1.017a 
9.8 
9-3 
S’45 
S’46 
x.0266 
x.0225 
4«5 1 . 
3-o 
8.0 
5*41 
5-03 
1.0193 
1.0197 
10.3 
ix. 6 
5*37 
s-40 
1.0238 
1.0296 
3 *. 
3-3 
5-6 
5- 50 
5- as 
1.0x66 
1.0x90 
9.4 
10.3 
5* 5 2 
5-46 
1.0316 
1.0358 
97*. 
3-5 
4-3 
5*35 
S-as 
1.0180 
x.0148 
10.4 
xo. 9 
S’43 
5’ 47 
x.0239 
1-0253 
35©. 
a-3 
6.9 
S-69 
S-19 
1.0176 
1.0303 
9.0 
11.9 
S* 43 
S*4a 
X.03I3 
1.0261 
326. 
2. e 
8.3 
<• CQ 
c. 16 
I, 0134 
8.4 
14*9 
C, <0 
5*33 
x. 0204 
1.0261 
315. 
4 j 
36 
6.0 
5-35 
J* 
S’as 
1.0x66 
1.0X74 
10-4 
9.8 
5*31 
S’43 
X.0234 
x.0229 
**9. 
3.8 
6.6 
S’ 44 
5.16 
1.0143 
X. OI44 
10.3 
10.7 
5-37 
S-44 
1.0336 
1.0x97 
XI3. 
1.8 
5* 60 
1.0194 
9.6 
5*4° 
. X.02XX 
Average. 
3.8 
6.3 
5-Si 
S* 19 
j 1.0171 
I.OX75 
9.7 
XX. 2 
S’4* 
5-43 
1.0229 
x. 0348 
1 The plants erf strain 485 in Series V appeared wilted when cut. This probably accounts for the unusually 
high acidity and hydrogen-ton concentration of the stalks and the high specific gravity of both stalk and 
leaf juice of those plants. 
The data in Table V show that the stalk juices of the rapidly growing 
greenhouse plants of Series IV had a decidedly lower titratable acidity 
and hydrogen-ion concentration than did those of the stunted ones 
from the outdoor plot (Series V). That the stalks of these slow-growing 
plants are characterized by a relatively high acid accumulation rather 
than simply a high sap density due to an increased concentration of all 
the solutes is shown by the fact that the specific gravity figures bear no 
consistent relation to the acidity measurements. 
In some of the strains there is no significant difference in the acidity 
values for the leaf juices of the good and the poor series. The acidity 
of the stalk appears to be affected in greater degree by the environment 
than does that of the leaves. There are some data reported in the 
literature pointing to this same fact. Thus, with different fertilizer 
treatments, Bauer and Haas (3) obtained variations in the actual acidity 
in the stalks of corn between P H 5.31 and 5.95; and in the leaves between 
5.31 and 5.49. Haas (<8) found also that liming the soil decreased the 
actual and total acidities of the juice of the stems and petioles of red 
clover plants more than it did that of the leaves. 
Consistent with the evidence that the concentration of titratable acid is 
higher in the leaves than in the stalk of the same plant are the specific- 
gravity measurements in Table V, which show that in every plant of each 
series, whether vigorous or stunted, there is a much higher sap density 
in the leaves than in the stalk. However, in all the stunted plants of 
Series V the hydrogen-ion concentration of the stalk juice was much 
higher than that of the leaves, although the titratable acidity was very 
much lower. In the vigorous plants of Series IV the lower concentra¬ 
tion of hydrogen-ions accompanied the lower titratable acidity in the 
stalk, except in a few instances where the P H values were practically 
the same. Furthermore, the ratio of the titratable acidity of the stalk 
to that of the leaves, which was 1 to 3 or 1 to 4 and sometimes even 
