56 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
Very little difference was noted as to degree of injury between shaded plants 
in ditch water and shaded plants in pond water. This indicates that nothing 
in the quality of the water aside from lack of oxygen caused the injury. 
The plants that were submerged but not shaded suffered little or no injury. 
Analyses of the water show that in these tubs the oxygen content decreased 
only during the night and did not remain long at a low level. The shading 
during the day prevented the accumulation of oxygen which would have 
carried the plants through a considerable part of the night. Cloudiness 
would have the same effect, the effect being more pronounced with greater 
reductions of light. 
In this connection, attention may be called to the rate of respiration of 
the flowers and of the young and old shoots of cranberry plants as measured 
by the rate of production of carbon dioxide per unit of weight material. 
The experiments were made with Early Blacks. A weighed amount of 
flowers, growing tips, and old shoots was placed in closed receptacles of 
known volume. Determinations of carbon dioxide were made at definite 
intervals after the experiment was started. Analyses were made with an 
Allen-Moyer Orsatt apparatus. The readings were corrected to show the 
volume of dry gas at o° C. and at a pressure of 760 mm. The results are 
given in table 2. 
Table 2. A comparison of the carbon dioxide production of flowers, growing tips, and old 
shoots of cranberries 
Carbon Dioxide 
Dace 
Material 
Weight 
in Grams 
Volume 
in Cc. 
Duration 
of Experiment 
Temp. 
C. 
% 
Observed 
Cc. per 
Hour 
Cc. per 
Hour per 
100 G, 
July 7 
Flowers 
Growing tips 
Old shoots 
Flowers 
Growing tips 
Old shoots 
II.O 
19.0 
36.5 
II.O 
19.0 
36.5 
25 
35 
54 
25 
35 
54 
2 h. 15 m. 
2 h. 20 m. 
2 h. 15 m. 
15 h. 10 m. 
22° 
0.4 
0.7 
0.5 
2.0 
3.0 
2.6 
4.2 
7-1 
5.2 
2.5 
3-7 
3-3 
38.6 
37-4 
14.3 
22.0 
19-3 
6.1 
Flowers 
Growing tips 
Old shoots 
13-7 
25-9 
40-5 
26 
39 
57 
I hour 
25-5 
0.45 
0.5 
0.5 
10.5 
11.6 
11.5 
76.5 
46.2 
28.3 
Flowers 
Growing tips 
Old shoots 
13-7 
25.0 
40-5 
26 
39 
57 
2 hours 
27-5 
27.5 
0.5 
I.O 
0.6 
II-5 
22.9 
13-7 
42.0 
45-8 
16.9 
Flowers 
Growing tips 
Old shoots 
13.7 
25.0 
40-5 
26 
39 
57 
28.0 
0.5 
0.9 
0.5 
II-5 
20.6 
II-5 
41.8 
41.0 
14.0 
From the results of these experiments it is evident that under the same 
temperature conditions the flowers and growing tips show a much higher 
rate of production of carbon dioxide than do the old shoots. Nicolas (4, 
p. 109), in some twenty plants studied, found respiration more rapid and 
