Dec. 18,1916 Influence of Bordeaux Mixture on Transpiration 541 
vary on either side of the average ratios for the standardization period. 
In this experiment with cabbage plants it may not, therefore, be stated 
with entire certainty that an application of Bordeaux mixture has an 
accelerating influence on the rates of water loss, since the difference be¬ 
tween the ratio values for the periods before and after treatment are no 
greater than might be expected to lie within the limits of experimental 
error. On the other hand, the spray was applied only to the upper sur¬ 
faces of the leaves, so that only one-half of the transpiring surface was 
affected by the spray material. Furthermore, stomatal transpiration 
from the upper surfaces of the leaves should be somewhat less than from 
the lower surfaces, considering the number of stomata per square milli¬ 
meter on the upper leaf surface to be 219 and that on the lower surface 
to be 301, according to Duggar (5, p. 91). This would still further tend 
to minimize any accelerating influence which the spray might have on the 
rates of water loss. 
PEPPER PlyANTS 
The plants used in the experiment with peppers were very uniform in 
size, about 8 inches tall, vigorous, and were just beginning to bloom when 
the experiment was begun. The experiment continued during a time 
period of 16 days. The standardization period extended from February 
26 to March 3; the period after treatment continued from March 3 to 
March 14. The results of this experiment are given in Table IV. The 
arrangement of this table and subsequent ones is precisely the same as 
that employed in the presentation of the data for the experiment with 
cabbage plants. 
Table IV .—Effect of Bordeaux mixture on the rate of transpiration of potted pepper 
plants 
[Period before treatment, Feb. 26 to Mar. 3; period after treatment, Mar. 3 to Mar. 14, 1916J 
Plant No. 
Transpiration quantities. 
Green weight 
of tops. 
Dry weight 
of tops. 
Period before 
treatment. 
Period after 
treatment. 
Series 
A. 
Series 
B. 
Series 
A'. 
Series 
B. 
Series 
A'. 
Series 
B. 
Series 
A'. 
Series 
B. 
(A) 
(B) 
(AO 
(B) 
(G) 
(GO 
(D) 
(DO 
38.x 
35-7 
109.3 
43*0 
3 * 70 
5* 02 
0*75 
0.83 
37*9 
17.0 
91*4 
37*7 
2. 08 
2-57 
■45 
•31 
3*-4 
27.9 
63- 3 
42. s 
4 * 57 
2.25 
.70 
.40 
37-3 
40.0 
102. 8 
103*3 
4 * 4 ° 
4 - 8 7 
•65 
* 73 
29* 8 
32*9 
65. 2 
54 * 7 
4. 20 
4-73 
•69 
*78 
6. 
S 7 * 9 
20. 9 
114. 8 
37*9 
6.80 
2* 75 
I. 12 
*47 
Average.. 
38.7 
29.0 
91.1 | 
53 * 1 
4. 29 
3 * 69 
.72 
.58 
Transpiration.ratio.. 
AB= 
= 1.33 
A'B=i. 7 i 
Difference. 
. 0.38+ 
Water loss per gram of green 
substance.ratio.. 
AG' BG=i.i 4 
A G BG=x. 47 
Difference. 
. .33+ 
Water loss per gram of dry sub¬ 
stance.ratio.. 
AD' BD=i.o7 
A D BD==i,37 
Difference.. 
. .30+ 
