JOURNAL OF AGBCCLTDRAL RESEARd 
DEPARTMENT OF AGRICULTURE 
Vol. V Washington, D. C., December 27, 1915 No. 13 
CARBOHYDRATE TRANSFORMATIONS IN SWEET 
POTATOES 
*» 
By Heinrich Hasselbring and Lon A. Hawkins, Plant Physiologists , Drug-Plant , 
Poisonous-Plant , Physiological , and Fermentation Investigations , Bureau of Plant 
Industry 
INTRODUCTION 
In a former paper 1 embodying a study of the general course of the 
carbohydrate transformations in sweet potatoes {Ipomoea batatas) 
during storage, certain data were presented indicating that the sugar 
content of sweet potatoes remains comparatively low while they 
are in the ground, but that immediately after the roots are harvested 
there is a transformation of starch into sugar which takes place more 
rapidly at that time than at subsequent periods. It was pointed out 
that this initial transformation seemed to be not greatly affected by 
temperature, but seemed rather to depend upon internal factors. It 
was suggested that possibly this initial change was associated with the 
cessation of the activity of the leaves. In view of the fact that this 
initial change appeared to be a phase of the carbohydrate metabolism 
of the sweet potato which was inaugurated only under certain conditions 
and which differed in some respects from subsequent changes, it seemed 
worth while to investigate this process more fully in order to make out 
something, if possible, as to its nature by a study of its progress at dif¬ 
ferent temperatures. 
EXPERIMENTATION IN CARBOHYDRATE TRANSFORMATION 
PLAN OF EXPERIMENTS 
The plan carried out in this work was, in general, to compare the 
carbohydrate transformations taking place in sweet potatoes during a 
period of io or 12 days immediately after they had been dug with the 
changes taking place during a second subsequent period of equal length. 
These experiments were carried out at temperatures of 30°, 15.5 0 , and 
5 ° C. 
1 Hasselbring, Heinrich, anU Hawkins, L. A. Physiological changes in sweet potatoes during storage. 
In Jour. Agr. Research, v. 3, no. 4, p. 33i~34 2 * 1915- Literature cited, p. 341-342. 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
bo 
(543) 
Vol. V, No. 13 
Dec. 27,1915 
G —70. 
