12 
BULLETIN 56, HAWAII EXPERIMENT STATION 
sugars and found that the reducing sugars, which up to that time 
had been considered as glucose, consist of both levulose and dextrose. 
The presence in the leaf of large quantities of sucrose and the nature 
of its fluctuations led to the conclusion that sucrose is the first sugar 
produced by photosynthesis, and that levulose and dextrose are the 
products of hydrolysis 
of the sucrose. 
Davis, Daish, and 
Sawyer (6) , in studying 
the carbohydrates of the 
mangel leaf, and Davis 
and Sawyer (5), in 
studying the potato 
plant, found that, 
whereas in the leaf 
sucrose predominates, 
the hexoses are in excess 
of the sucrose in the 
midribs and stems. 
From this they con- 
cluded that sucrose is 
the " primary sugar 
formed in themesophyll 
of the leaf under the 
influence of the chloro- 
phyll," and that "it is 
transformed into hex- 
oses for the purpose of 
translocation" (6, p. 
314). Strakosch (14) 
took the opposite view. 
Using mic'rochemical 
methods, he concluded 
that dextrose is the first 
apparent sugar to 
appear. The appear- 
ance of levulose, and 
later of sucrose in the 
leaf veins, led him to 
believe that sucrose is 
the final sugar and is 
transported as such 
through the stem. 
Pellet, in a discussion 
with Vivien (15, p. 173), concludes that sucrose, dextrose, and 
levulose are formed simultaneously in the leaf and descend to the root 
as such. 
The variations of sugars at different stages of maturity of the 
plant have been studied by different investigators. Colin (4) found 
that, in the early stages of growth of the sugar beet root, the reducing 
sugars may form as much as 20 per cent of the total sugars. As the 
root matures the proportion of reducing sugars to sucrose decreases, 
but the former are never entirely absent and are always most 
abundant at the growing tip. Davis (6) and his associates, work- 
Fig. 7.— Different stages in the development of the bud. The 
stem of the large offspring is developing, resulting in a sharp 
decrease in cell growth at the apex of the rootstock. This has led 
to vigorous development of its bud. The bud on the parent 
rootstock has failed to develop, and probably would eventually 
result in a small secondary rootstock 
