490 



Journal of Agricultural Research 



Vol. XIX, No. lo 



as the season advanced. While the data are much too limited to justify 

 the assumption that this relation of acidity to latitude generally holds, 

 the results of the one year's work are of sufficient interest to warrant 

 further study along this line. 



KFFECT OF STORAGE UPON ACIDITY 



A somewhat greater uniformity exists in the relation of temperature 

 of storage to the acidity of the ripened product than was found in 

 connection with the time of picking. In the first place, it will be noted 





so 



JO 



s /o 



2S 



JO 



/iUGUST 



/^ 



Fig. s. — Acids in Bartlett pears from Sacramento, Calif.: Curve i, acid in green fruit when picked from the 

 tree; curve 2, acid in collateral lots after ripening at 70° F.; curve 3, acid in collateral lots after ripening 

 at 40°; curve 4, acid in collateral lots after ripening at 30°. 



that in the early picks there is a wide variation in amount of acid, due 

 to the temperature of the storage used; and in most cases there is a 

 greater amount of acid in the green fruit than in the ripened fruit, 

 regardless of the temperature at which it was held. Fruit picked in a 

 very immature condition has less acid when ripened than at the time 

 of picking. (Curves 1-4, fig. 5-6, early pickings.) 



Fruit picked at about the time of the opening of the commercial season, 

 however, behaved somewhat differently. In every case the fruit ripened 

 at 70° F. contained a higher percentage of titratable acid than did the 

 same fruit when picked from the tree. This is of interest especially in 

 connection vath the question of whether fruit acids are synthesized in the 

 fruit itself or whether they are carried to the fruit from the leaves. The 

 fact that there is an increase in the acid between the time the fruit is 

 removed from the tree and the time of its becoming ripe is evidence that 

 there is an actual synthesis of acid in the fruit itself. 



