Dec, 1922] RUTH EFFECT OF BORDEAUX MIXTURE 
543 
the gram of fresh weight was still more marked. From this period on there 
was a decrease in the amount of chlorophyll to the square centimeter and 
gram of fresh weight, which was associated with an increase in the fresh 
weight of the leaf per square centimeter and a lessened rate of increase in 
area. This decrease was not so great that neutralization of any effect of 
early spraying was anticipated before ''Age D'' was reached. The necessity 
was recognized of comparing plants harvested only at the same stage 
of development. 
The correlation between rapid growth and high chlorophyll content was 
determined also in the following way: To accelerate and increase the growth 
of the primordial leaves of certain plants, the growing buds above them 
were kept cut off. The primordial leaves of such plants became much 
larger, thicker, and greener than the primordial leaves of the check plants 
among them. Measurements of the area and weight were made when the 
plants were picked, which was four days after the cotyledons were shed 
Table 2. Effect of Removal of Growing Buds upon Growth and Chlorophyll Content of 
Primordial Leaves 
Flat 
Average Area 
Both Leaves 
Average Weight Both 
Leaves per sq. cm. 
Average Chlorophyll 
per sq. cm. 
Average Chlorophyll 
per g. Fresh Wt. 
Check 
Buds 
Removed 
Check 
Buds 
Removed 
Buds 
Check j Removed 
Check 
Buds 
Removed 
Sq. 
cm. 
Sq. 
cm. 
% of 
check 
G. 
G. 
% of 
check 
wt. 
(mg.) 
wt. 
(mg.) 
% of 
check 
wt. 
(mg.) 
Wt. 
(mg.) 
% of 
check 
I 1 76.9 
II9.9 
154 
O.OI81 
0.0225 
124 
0.0315 
0.0454 
144 
1.74 
2.02 
116 
2 83.2 112. 1 
135 0.0186 
0.0241 
129 
0.0353 
0.0524 
148 
1.89 
2.17 
115 
3 1 93.2 1 127.7 
137 1 0.0199 
0.0251 
126 
0.0381 
0.0527 
138 
I.9I 
2.10 
no 
Ave. 1 
142 
126 
143 
|ii4 
("Age C"). The leaves from the plants similarly treated in each flat were 
dried, and their chlorophyll content was determined together. The figures 
presented in table 2 are half-flat averages. Three flats were used, in which 
forty-two plants were grown. A greater chlorophyll content per square 
centimeter was plainly produced, which was to be accounted for only 
partly on the basis of a greater weight of a unit area of leaf ; the average 
increase in the chlorophyll per square centimeter was 143 percent, while the 
weight of the leaf per square centimeter was increased only 126 percent. 
An actual increase in the amount of chlorophyll in a unit weight of fresh 
leaf (114 percent) was thus an important factor. The average increase in 
chlorophyll per square centimeter (143 percent) corresponded with the 
average increase of 142 percent in the rate of expansion of the whole leaf 
in area. 
