CARBOHYDRATE METABOLISM AND GROWTH IN EDIBLE CANNA 27 
all the nutrition from the parent stem. In addition to these old 
rootstocks, the hill contains the dormant rootstocks (Group 1 stage), 
the stems of which develop normally and then die back. The sugars 
of the mature "stemless" rootstocks are of interest because they 
represent the residual components of the rootstocks unaffected by 
incoming materials from the stem. 
Table 10 shows the sugar content of a number of rootstocks which, 
for one reason or another, were devoid of stems. 
Table 10. — Sugars in sap of mature rootstocks devoid of stems 
Description of rootstock 
Sucrose 
Hexoses 
in sap 
in sap 
Per cent 
Per cent 
1.61 
0.19 
.98 
.22 
2.08 
.22 
1.09 
.00 
2.65 
.15 
.51 
.01 
Total 
sugars in 
sap 
Dormant; stem dead 2 
Nonirrigated; stem removed 5 months previous 
Irrigated; stem removed 5 months previous 
Old, nonirrigated; spike dead 3 
Old, irrigated; spike dead 
Old, grown at Waimea; spike dead 
Per cent 
1.80 
1.20 
2.30 
1.09 
2.80 
.52 
1 All samples, except No. 6, were grown at the station. 
2 Sample No. 2 of Table 4. 
3 Attached to sample No. 2. 
The table shows that sample No. 1, the stem of which developed 
normally and subsequently died, had a comparatively high sucrose 
content. Sample No. 2, the stem of which had been removed while 
still green, and sample No. 4, the spike of which had died, showed 
decidedly lower concentrations of sucrose. The increase of sucrose 
content of samples Nos. 3 and 5 to more than double that of samples 
Nos. 2 and 4, respectively, further substantiates the theory previously 
advanced (p. 26) that increase in sucrose may be due to hydrolysis 
of the starch already formed in the rootstock, rather than to trans- 
location from the stem, since the rootstocks were devoid of stems. 
Sample No. 4 was expected to represent the minimum concentration 
of both sucrose and the hexoses possible within a rootstock because 
it was supporting no growth and was attached to sample No. 2, 
which was without stem development. The hexose content was nil 
but the percentage of sucrose was not outstandingly low, sample No. 
6, which was an old rootstock with dead spike, having less than half 
the quantity. 
An abnormally low sucrose content in a mature rootstock has been 
frequently observed to accompany a low percentage of starch (deter- 
mined by the specific gravity method) , suggesting the possibility of 
the sucrose of the rootstock being in some sort of equilibrium with 
its starch, since a low sucrose content results from a cell structure 
"unsaturated" with starch, and a high sucrose content from a cell 
structure having a high starch content. This theory seems to be 
confirmed by Table 9, which shows that samples from the unirrigated 
section of station field 26A had a higher sucrose content than those 
from station field 32C, on which the crop became stunted before any 
of the rootstocks reached full maturitv. 
