122 
AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
Table 2. 
Comparative losses of water from attached and detached lemons as shown by the 
freezing-point method 
No. 
of 
Test 
Nature of Tests 
Lemons detached from branches at once.. 
Lemons detached from branches after 
being in oven 4^ hours at 46° C. 
1 
2 
Lemons detached from branches at once. . 
Lemons detached from branches before. . 
being placed in oven 4J hours at 46° C.. . 
Mean 
Mean 
Concentrations 
A 
(atmospheres) 
f Stylar end. 1.077 
12.96 
(stem end.. 1.062 
12.79 
[Stylar end. 1.193 
H -35 
[Stem end.. 1.198 
14-37 
[Stylar end. 1.182 
14.22 
[Stem end.. 1.150 
13.84 
[Stylar end. 1.192 
14-35 
[ Stem end. . 1.196 
14.39 
The results in the first half of table 2 show that there was a marked 
increase in the concentration of the juice in the lemons that were in the oven 
for hours, the increase being 1.39 atmospheres for the stylar end and 
1.58 atmospheres for the stem end. That this increase in concentration 
could not have been due, to any marked extent, to water passing out 
through the peel of the lemons is shown by the figures in the latter half of 
the table, for here the stylar end shows a difference of only 0.13 atmosphere 
and the stem end one of only 0.55 atmosphere. The marked difference 
between the first and second tests is due to the fact that the first was made 
about 6 weeks earlier than the second one. At the time of making the 
earlier test the trees were still growing, and the determinations were made 
after irrigation and a light rain followed by heavy dews at night. This, 
of course, would tend to make the fruits more turgid, and hence to reduce 
the sap concentration. 
5. The. results of another experiment are offered as further proof that 
the leaves may draw water from the fruits. Branches about 60 cm. long, 
each bearing from 1 to 3 lemons, were cut from the trees and at once cut 
again under water. These branches were then brought to the laboratory, 
placed with the cut ends in jars of water, and all set in a well-ventilated oven 
heated by electricity. During the day the oven temperature ranged from 
35 to 38° C. About 5 p.m. the heat was turned off and not turned on again 
until about 8:30 a.m. the next day. The temperatures at night ranged 
from about 15 to 18 0 C. The leaves on the branches under these con¬ 
ditions retained a normal appearance for about 5 to 7 days. At the end 
of this time they began to wilt and lose their luster. By the end of 8 to 10 
days the leaves began to drop. About this time the lemons were taken 
from the branches and thin slices were cut from the stylar ends, the knife 
passing through the point of juncture of pulp and peel. Observation of 
the cut surfaces showed that in a large number of the lemons, though not 
