544 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9, 
The Effect of Bordeaux Mixture 
The experiments immediately following were to determine, by measuring 
the length of sprayed and unsprayed leaves, (i) how soon after spraying 
young primordial leaves, just unfolding, the effect upon growth was to be 
observed; (2) whether the growth rate was increased or decreased; (3) 
when the effect was most manifest; and (4) whether any such effect was 
outgrown. A quickly manifested effect was anticipated in view of the 
rapid growth of the leaves and the quickly manifested effect of Bordeaux 
mixture upon transpiration (Martin, 191 6). 
Five flats were planted to beans, one flat at a time, at intervals of from 
one to five days. The total period of planting covered eighteen days, and 
the plants were exposed, on that account, to slight variations in weather 
conditions. As soon as the primordial leaves had unfolded, the plants in 
one half of each flat were sprayed with Bordeaux mixture. The length of 
the leaves was determined at that time and at intervals of two, four, eight, 
twelve, and fourteen days after spraying. Measurements made on the 
fourteenth day gave the same average lengths as those made on the twelfth. 
No measurements made after the twelfth day are presented. 
Although the average length of the sprayed leaves in three of the five 
flats somewhat exceeded the length of the leaves not to be sprayed when 
the experiment was started, the sprayed leaves in all the flats were the 
shorter at the conclusion of the experiment. The effect in decreased growth 
was plainly evident on the second day, and probably could have been 
observed earlier. On the fourteenth day the relative differences to be 
observed on the second day had not been overcome. The results are 
summarized in table 3. 
Table 3. Effect of One Application of Bordeaux Mixture as Shown hy a Lessened Growth 
in Length 
Days after 
Sprayingi 
Treatment 
Sprayed. . . 
Unsprayed 
Sprayed. . . 
Unsprayed 
Sprayed . . . 
Unsprayed, 
Sprayed . . . 
Unsprayed 
Sprayed. . . 
Unsprayed. 
Average Length Primordial Leaves (cm.). 
Flat Number 
6.1 
6.1 
6.8 
7-1 
7.2 
77 
7.6 
8.2 
7-7 
8.3 
4- 3 
4.1 
54 
5- 6 
6.4 
6.5 
7.0 
7.2 
7-3 
74 
4.6 
44 
5-9 
5-9 
6.8 
6.9 
7.6 
7.8 
7-7 
7-9 
3-9 
3.6 
5-5 
5-8 
6.6 
6.9 
7-7 
7.8 
7-9 
8.3 
3-3 
34 
4.8 
4.9 
5-9 
6.3 
6.3 
6.5 
7.2 
7.8 
Relation of Length 
of Sprayed to Unsprayed 
Leaves in Percentages 
103 
97 
96 
96 
95 
^ The state of development of the plant when the leaves were sprayed is represented 
by "Age A'' in the preceding section; the fourth day corresponds with "Age and the 
eighth day with "Age C." 
