Jan. 5,1924 
Physiological Studies on Apples in Storage 
9 
siderable variation occurs in individual apples from the same tree, 
depending upon the nutrition of the individual apples. Ballard, Mag- 
ness, and Hawkins (r) have reported that apples from branches of Yellow 
Newtown trees which were girdled in June contained distinctly more 
acid, as well as more total sugar, than did apples from normal branches 
of the same trees, while fruit from partially defoliated branches on the 
same trees showed still less acid than the untreated checks. 
In other works by the same investigators (unpublished) acidity deter¬ 
minations were made on fruit from a large number of Yellow Newtown 
trees during each of three succeeding seasons. These trees were about 
20 years of age, and during the first and third seasons produced only a 
very light crop, averaging 1 to 6 bushels per tree. During the second 
season under test, however, the crop was very heavy. It was found 
that the average acidity in fruit from the same trees was fully 25 per 
cent higher during the “off ” or light crop years than during the season 
of heavy production. These figures represent an average of about 70 
individual trees. Furthermore, during the “off” year acidity was 
much lower on the average in the trees bearing a fairly full crop. 
It is apparent, then, that there is a close association between acidity 
in apples and the nutritive conditions in the tree upon which they were 
produced. Climatic conditions also are of undoubted importance, 
although they have not been carefully studied. Acidity is of much 
importance in determining quality in fruit not only as relates to growing 
conditions, but as regards storage as well, for it is intimately associated 
with flavor. 
CHANGES IN WATER CONTENT OP THE FRUIT 
The change in water content of the fruit as it matures on the tree 
is less marked than changes in sugars. The percentage of water in the 
fruit will vary widely with variation in soil moisture. Conditions of 
soil moisture being uniform throughout the season, however, there is a 
slight decrease in the amount of water and an increase in dry matter 
as the season progresses. This change is not marked, but is borne out 
by the results obtained by Bigelow, Gore, and Howard (2), by Burroughs 
(5), and by other investigators. 
CHANGES IN SUGARS AND STARCH DURING GROWTH 
The literature regarding changes in sugar in fruit during its ripening 
on the tree is equally as voluminous as that regarding acidity changes. 
The following summary is based on the work of Bigelow, Gore, and 
Howard (2) which included a careful study of the sugar changes in apples 
both while attached to the tree and while held in storage following 
picking. 
During early summer (June) the total sugar content of all the winter 
varieties was low, running from 3 to 4 per cent of the weight of the green 
tissue. In both summer and winter varieties, the percentage of total 
sugar increased steadily until the fruit was dropping badly, that being 
late July for the summer varieties (Early Strawberry, Bough, and 
Yellow Transparent) under West Virginia conditions, and late October 
for the winter varieties (Ben Davis, Huntsman, and Winter Paradise). 
During the early season, the sugar is largely in the form of reducing 
sugars, but as the season advances there is a marked increase in the 
