Oct. 29. 192 1 Physiological Study of Grapefruit Ripening 



277 



and warm storage render it resistant. This, of course, is somewhat 

 doubtful. The case is somewhat analagous to that cited by Winston 

 (15) in regard to tear stain, which has up to now been considered to be 

 due to Colletotrichum gloeosporioides, mainly because this fungus was 

 usually found in cultures from the diseased areas. In the present work 

 it seems fair to conclude that whether or not the fungus causes the pit- 

 ting it is controlled at least to a large extent by curing before placing the 

 fruit in cold storage. 



Table V. 



-Results of cultural experiments with pitted grapefruit and with fruit from 

 same lot which was unpitted « 



o Unless otherwise stated, all pieces of tissue were sterilized two minutes in i to 1,000 bichlorid solution 

 and were washed three times in sterile tap water before pouring plates. The control fruits were without 

 signs of the pitted spots under investigation. ' ' Between pits ' ' refers to sound tissue between the spots. 



GENERAL DISCUSSION AND CONCLUSION 



In the investigation of grapefruit storage described in the foregoing 

 pages it has been brought out that in warm storage the percentage of 

 acid calculated to the wet weight of the pulp increases markedly in two 

 months' storage. There is evidence that this increase is not due entirely 

 to loss of water from the pulp, but that there is an increase in the amount 

 of acid present. There is evidence indicating that there may be a slight 

 decrease in the sugar content in warm storage. In cold storage there is a 

 decrease in the acidity very marked after four months in storage, while 

 there is little change in the amount of total sugars present. A possible 

 explanation of this difference in the behavior of the sugars and acids in 

 warm and cold storage was pointed out. This phase of the problem 

 deserves further attention. The investigations on the changes in the 



