JOURNAL OF AOTLTURAl RESEARCH 
Vol. XXVII Washington, D. C., Jan. 5, 1924 No. 1 
PHYSIOLOGICAL STUDIES ON APPLES IN STORAGE 3 
By J. R. Magness, Physiologist , and H. C. Diehl, Junior Physiologist , Office of 
Horticultural Investigations , Bureau of Plant Industry , United States Department 
of Agriculture 
The successful holding of apples in storage is of great importance in 
this country, not only from the point of view of the commercial fruit 
industry, but from the viewpoint of the consuming public as well. Fresh 
fruit is assuming a position of increasing importance in the diet of the 
human race. The marketing of the fall and winter varieties of apples 
direct from the tree is practically limited to three months of the year. 
If a supply of this fruit is to be available throughout the year, storage 
suitable for holding the fruit is essential. Not only does proper storage 
insure a supply of a necessary food material throughout the year, but it 
also greatly stimulates consumption and stabilizes prices for the fruit 
grower. 
Although much study has been devoted to the question of proper 
storage conditions for apples and other fruit, the problems involved are 
so complex that many questions remain unanswered. The factors of the 
exact influence of time of picking, storage temperature, humidity, ventila¬ 
tion, etc., upon the physiological ripening processes in the fruit are not 
perfectly understood, and many inaccurate impressions exist in regard 
to their functions in storage management. 
In the studies here reported, the literature concerning the chemistry 
and physiology of the ripening processes in apples have been freely drawn 
upon and correlated with the investigations on the storage life of the 
fruit made by the authors. 
THE RIPENING OF APPLES ON THE TREE 
For a proper understanding of the changes that occur in apples while 
in storage, it is important that the processes of growth and development 
of the fruit while on the tree be considered. The physiological changes 
in the apple fruit from the time of blossoming until ultimately consumed 
or until the end of its life is reached are continuous. The conditions 
under which the fruit is grown and the time of picking have an impor¬ 
tant bearing upon the storage behavior of the fruit. 
PHYSICAL CHANGES DURING DEVELOPMENT OF THE FRUIT ON THE TREE 
Among the most important of the physical changes in apples during 
development and ripening on the tree may be mentioned increase in 
size, changes in color, changes in the skin texture, and changes in hard¬ 
ness of the flesh. These changes are all intimately associated with 
storage quality in apples. •- - 
1 Accepted for publication Nov. 19, 1923. 
2 This paper gives the results of a portion of the work carried on under the project “Factors Affecting 
the Storage Life of Fruits.” 
Journal of Agricultural Research, Vol. XXVII, No. 1 
Washington, D. C. Jan. 5, 1924 
Key No. G-347 
73430—24-1 
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