26 
BULLETIN 56, HAWAII EXPERIMENT STATION 
Table 9. — Effect of irrigation on the sugars of stunted plants 
HILL NO. 1, STATION FIELD 32C (PLANTED JAN. 10, 1925) 
Date of 
harvest 
Period of 
irrigation ! 
Sucrose in sap 
Hexoses in sap 
Total sugars in sap 
Specific, 
gravity 
of 
rootstock 
Rootstock 
Stem 
Rootstock 
Stem 
Rootstock 
Stem 
1 
1925 
July 21 
...do 
July 28 
Aug. 14 
Sept. 8 
Apr. 8 
Days 
11 

18 
35 
60 

Per cent 
0.71 
.56 
.66 
.59 
.60 
1.65 
Per cent 
0.29 
.31 
.46 
.30 
.29 
.36 
Per cent 
0.24 
.15 
.29 
.24 
.18 
.72 
Per cent 
0.43 
.18 
.33 
.51 
.39 
.54 
Per cent 
95 
.71 
.95 
.83 
.78 
2.37 
Per cent 
0.72 
.49 
.79 
.81 
.68 
.90 
*2 
3 
4 
5 
36 
1.041 
1.053 
1.048 
1.036 
.991 
HILL NO. 2, STATION FIELD 26A (PLANTED JAN. 10, 1925) 
7 
July 25 
...do.... 
Aug. 26 
...do.... 
Sept. 2 
...do.... 
Dec. 4 
15 

32 

39 


1.16 
1.16 
2.47 
1.30 
2.83 
1.03 
1.29 
0.08 
.13 
.21 
.19 
.22 
.15 
.21 
1.24 
1.29 
2.68 
1.49 
3.05 
1.18 
1.50 
1.063 
28 
9 
2 10 
11 
212 
.80 
.50 
.58 
.29 
.77 
0.91 
1.20 
.79 
.42 
1.85 
1.71 
1.70 
1.37 
.71 
2.62 
1.068 
1.070 
1.066 
»13 
1.071 
'Irrigation begun July 10, 1925. 
2 Unirrigated portion of the field. 
3 Harvested at optimum growth. 
The results show no increase in the sugars in the stunted plants of 
station field 32C after two months of constant irrigation. If the 
specific gravity of the rootstocks is used as an index of their starch 
content the starch is seen to have made no increase during the 
period, and the very low hexose content of the stem shows that 
only a very small quantity of sugar was being transported down the 
stem. In the unstunted plants of station field 26A, however, not 
only did the sucrose in the rootstocks increase, but the increase was 
more than double that of the hill during its optimum growing period 
notwithstanding the uniformly low hexose content of the stems and 
the almost constant specific gravity of the rootstocks. In both plats 
the new growth resulted in very small rootstocks and stunted stems, 
with even the second generation of renewed growth decidedly under- 
sized. 
The above apparent contradiction may be explained by the fact 
that the increase in sucrose in field 26A was in reality due to break- 
ing down of the starch previously stored in the rootstock to nourish 
the buds developing on even the oldest rootstocks of the hill; whereas, 
in a vigorously growing hill the plant food is supplied by the parent 
stem. Failure of the sucrose to increase in case of field 32C may 
have been due to the fact that the hill selected for analysis was 
younger and the developing buds were on the youngest rootstocks 
the stems of which retained sufficient vitality to support a stunted 
new growth. 
MATURE ROOTSTOCKS DEVOID OF STEMS 
Many old rootstocks, the stems of which always remain as ° spikes/' 
form a part of every hill of canna. Failure to develop stems may 
be due to the death of the meristem, as evinced by blackening of the 
apex, or to the increased vigor of the offspring which take practically 
