34 BULLETIN 56, HAWAII EXPERIMENT STATION 
In the mature rootstock the sucrose content varies greatly under 
different conditions. Indications are that it exists in some sort of 
equilibrium with the starch, since the sucrose content is low in root- 
stocks having a low starch content and high in those having a high 
starch content. 
When stem growth has not been injured during the dormant 
period, new growth with rootstocks of fairly good size is produced, 
whereas stunted stems produce extremely stunted rootstocks. 
The percentage of starch varies widely in canna rootstocks of dif- 
ferent stages of maturity. Starting with a low content in the very 
young rootstock, the starch increases up to the dormant stage of the 
rootstock, the increase being accompanied by an increase in specific 
gravity. Graphs of the starch show that although the " growth 
curve " of different hills varies somewhat the correlation between 
specific gravity and the percentage of starch is general. A table has 
been constructed (Table 5, p. 11), which makes it possible to deter- 
mine in the field or the factory the approximate percentage of starch 
in a rootstock from its specific gravity. 
Determinations of osmotic pressures by cryoscopic measurements 
were made with a limited number of plants. The results confirm 
the general conclusions regarding growth drawn from the study of 
the carbohydrate metabolism of the plant. 
LITERATURE CITED 
(1) Association of Official Agricultural Chemists. 
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the committee on revision of methods. revised to nov. 1, 
1919. 417 p., illus. Washington, D. C. 
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(3) Chung, H. L., and Ripperton, J. C. 
1924. edible canna in Hawaii. Hawaii Agr. Expt. Sta. Bui. 54, 16 p., 
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(4) Colin, H. 
1914. SUR LA SACCHAROGENIE DANS LA BETTERAVE. Compt. Rend. Acad. 
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(5) Davis, W. A., and Sawyer, G. C. 
1916. STUDIES OF THE FORMATION AND TRANSLOCATION OF CARBOHY- 
DRATES IN PLANTS. III. THE CARBOHYDRATES OF THE LEAF AND 
LEAF STALKS OF THE POTATO. THE MECHANISM OF THE DEGRA- 
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7:352-384, illus. 
(6) Daish, A. J., and Sawyer, G. C. 
1916. STUDIES OF THE FORMATION AND TRANSLOCATION OF CARBOHY- 
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leaf. Jour. Agr. Sci. [England] 7:255-326, illus. 
(7) Harris, J. A., and Gortner, R. A. 
1914. NOTES ON THE CALCULATION OF THE OSMOTIC PRESSURE OF 
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(8) Knudson, L., and Ginsburg, S. 
1921. SUGGESTIONS WITH RESPECT TO THE MEASUREMENT OF OSMOTIC 
pressure. Amer. Jour. Bot. 8:164-170, illus. 
(9) Lutman, B. F. 
1919. OSMOTIC PRESSURES IN THE POTATO PLANT AT VARIOUS STAGES OF 
growth. Amer. Jour. Bot. 6:181-202, illus. 
(10) Meyer, A. 
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