CARBOHYDRATE METABOLISM AXD GROWTH IN EDIBLE CANNA 19 
The method of extracting sap by means of a meat grinder and 
screw press is not well adapted to the leaves of the canna plant 
because the sap is very viscous. Moreover, it was necessary to use 
all the leaves from a single stem to obtain enough sap for a deter- 
mination. Possibly a more complete extraction, using greater pres- 
sure as is suggested by Knudson and Ginsburg (8), might affect the 
results somewhat. The constancy of the data would seem sufficient 
to substantiate the essential correctness of the conclusions drawn, 
however. 
The very rapid rise of the hexoses and the decrease of sucrose in 
the midribs and sheaths and the continuation of these changes in the 
/./20 
/2 /5 /8 2/ 24 
peg cs/vr or sr^ecn 
Fig. 14.— Relation of specific gravity to percentage of starch in canna rnot.stocks 
stems is strong evidence in favor of the hexoses as ' ..■ ugars con- 
cerned in translocation. This is in accord with the finding * of Davis 
and Sawyer. 
In the stems of Group 2, hills 1 and 2, the hexoses still great I v 
exceeded the sucrose, but the latter showed an increase in concen- 
tration over that of the sheaths and midribs. This probably resulted 
from the functioning of the stem as a temporary storage organ. In 
the stem of the younger plant, hill 3, no such phenomenon occurred, 
the sucrose decreasing to a very low percentage. Evidently no stor- 
age of sugars occurred; in fact, the total sugars very markedly 
decreased. In explanation it may be said that the stem was in proc- 
ess of rapid growth during which food material was not stored, but 
rather diverted toward the apex of the stem. 
