THE UPWARD TRANSLOCATION OF FOODS IN WOODY 
PLANTS. 11. IS THERE NORMALLY AN UPWARD TRANS- 
FER OF STORAGE FOODS FROM THE ROOTS OR 
TRUNK TO THE GROWING SHOOTS? 
Otis F. Curtis 
There is apparently a very common belief that in most trees consider- 
able quantities of the carbohydrates, that have been stored in the lower 
trunk and in the roots, move up as growth starts in the spring and are used 
in shoot and leaf formation. 
The arguments which seem most commonly to be put forward as proof 
of such an upward transfer are that quantities of food are stored in the 
xylem tissues ; that these are present in soluble form in the water-conducting 
vessels at the time spring growth commences; and that these foods rapidly 
disappear at about the time of this rapid shoot development. From these 
facts it would seem reasonable to think that the food had moved up with 
the water to the growing shoots, but, as shown in a recent paper (Curtis, 
1920), the mere presence of soluble foods in water-conducting tissues cannot 
be considered as proof that the foods move with the water. In fact, it 
was shown that there is no appreciable longitudinal transfer of soluble foods 
through the xylem. 
Some ringing experiments of Hartig's (1858) have also been considered 
as proof of the movement of foods from the roots to the growing shoots. 
At intervals of eight days from the first of April, 1857, until the middle of 
September of the same year, he ringed young oak trees of about the diameter 
of one's arm. The rings were two inches broad and were situated four feet 
from the ground. Some trees were also cut down at the time of ringing, 
but he does not state whether these were cut early or late in the season. 
Observations made in the spring of 1858 showed that all trees ringed previous 
to June 30, 1857, had lost the starch from below the rings, while those ringed 
after June 30 contained starch. The starch from these also, however, had 
disappeared by the fall of 1858. As the starch had not disappeared from 
some of the roots of the felled trees, he concluded that the food stored in 
the roots normally moves up with the water through the xylem and is used 
in shoot growth. 
As has been previously shown, no appreciable quantities of food move 
longitudinally through the xylem and it seems very probable that the food 
below the rings disappeared because it was used in root growth and in 
diameter growth of the trunk. The only point tending to contradict this 
is that in some of the felled trees the starch did not disappear. This lack of 
286 
