HAWAII AGRICULTURAL EXPERIMENT STATION 
HONOLULU, HAWAII 
Under the supervision or the 
UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN NO. 56 
Washington, D. C. May, 1927 
CARBOHYDRATE METABOLISM AND ITS RELA- 
TION TO GROWTH IN THE EDIBLE CANNA 
By J. C. Ripperton, Chemist 
CONTENTS 
Page 
Habit of growth of the edible eanna 1 
Methods of investigation 5 
Carbohydrate metabolism .__ 11 
Cryoscopic measurements and osmotic pres- 
sure of the plant juices 30 
Page 
Discussion of results 32 
Summary.-.. 33 
Literature cited 34 
The potential importance of edible canna (Carina edulis) as a com- 
mercial source of starch has led to various experiments both at the 
central station in Honolulu and at Waimea, Hawaii. Although the 
plant is well known botanically, and has been grown in Queensland, 
Australia, for many years for starch, the available literature gives no 
information regarding its production on a field scale. Field methods 
of study devised by the station have given considerable data on the 
growth of the plant. Laboratory studies of the carbohydrate metab- 
olism of the plant have been made to learn the significance of the 
field results. 
HABIT OF GROWTH OF THE EDIBLE CANNA 
The edible canna belongs to the same genus as the familiar flower- 
ing variety, and resembles it both in appearance and manner of 
growth. Starting with the rootstock and the original stem, growth 
takes place through the development of axillary buds growing from 
the nodes of the rootstock. Growth within the hill is rapid when 
conditions are favorable. Development of the bud follows closely 
development of the parent, so that in a vigorous hill as many as 10 
plants, 1 representing three to five generations (fig. 1), maybe growing 
simultaneously. As the plant reaches maturity, first the leaves and 
then the stem shrivel, and the rootstock becomes dormant, while new 
growth continues through the developing buds. 
1 The term " plant " is used to denote a single rootstock and its attached stem. 
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