Dec, 1922] RUTH EFFECT OF BORDEAUX MIXTURE 
545 
It was apparent that if Bordeaux mixture resulted in a change in chloro- 
phyll content correlated with a decreased growth rate, one might expect 
such a change to be revealed soon after the spray was applied. It was 
concluded from the results of the above-described experiment that any 
differences in chlorophyll content brought about by the action of Bordeaux 
mixture applied early in the growth of the leaf would probably be preserved 
rather than materially lessened. 
The effect of Bordeaux mixture upon the development of chlorophyll 
may be indicated by reporting an experiment in which a set of six flats, 
planted on the same day, was used. The primordial leaves of one half of 
the plants in three of these flats were sprayed as soon as they had unfolded 
(flats 1,2, and 3 in tables 4-7). The same treatment was given to the 
primordial leaves of one half of the plants in the other three flats when the 
cotyledons were dropping (flats 4, 5, and 6 in the same tables), four days 
later. The plants in all six flats were harvested on the same day, three 
days after the later application, and seven days after the earlier one.^ 
At the time of spraying the average length of the sprayed leaves in all 
the flats was 5.7 cm., while those not to be sprayed averaged 5.9 cm. Flat 
averages of the areas and chlorophyll contents per square centimeter when 
the leaves were picked are presented in table 4. 
Table 4. Average Areas and Chlorophyll Content per Square Centimeter of Sprayed and 
Unsprayed Leaves 
Flat 
Area One Leaf (sq. cm.) 
Chlorophyll (m 
g. per sq. cm.) 
Sprayed 
Not Sprayed 
Sprayed 
Not Sprayed 
I 
48.7 
63-9 
.00436 
.00330 
2 
547 
62.4 
.00375 
.00401 
3 
57-2 
53-7 
.00382 
.00371 
4 
42.6 
45-9 
.00442 
.00399 
5 
61.2 
63-9 
.00340 
.00304 
6 
49.6 
57-6 
.00363 
•00356 
Ave. 
53-3 
57-9 
.00390 
.00361 
The chlorophyll content of unit areas of the sprayed leaves from all the 
flats with the exception of those from flat 2 was greater than that of the 
corresponding unsprayed leaves. The areas of the sprayed leaves were less 
than the areas of those not sprayed, with the exception of those from the 
plants grown in flat 3. The general results were anticipated in view of the 
darker color of the sprayed foliage and the stunting effect of the spray 
which had been manifested in the previous experiment in a lessened increase 
in length. 
The darker color was correlated with this smaller size. In spite of the 
lessened rate of expansion in area brought about by spraying, the chloro- 
2 This stage of development is referred to as "Age C" in the preceding section, where 
the state of unfolding is designated as "Age A " and that of cotyledon shedding as "Age B." 
