294 BOTANICAL GAZETTE [april 



i 



case in a normal season. This would be of especial value when 

 fruit was being harvested and packed for eastern shipment. Pears 

 are picked comparatively early in order to reach distant markets 

 in good condition. While they should preferably not be allowed 

 to ripen on the tree, to avoid the marked development of the grit 

 cells, it might mean that in excessively hot years, contrary to 

 expectations, the fruit could be left somewhat longer on the trees, 

 and thereby develop a better flavor and quality. If all varieties 

 of apples behave as do Yellow Newtown, high temperatures do 

 not delay ripening. Instead, up to the point of tissue destruction 

 by heat, the higher the temperature, the more rapid the ripening. 

 This emphasizes the necessity of hurrying into low temperatures 

 apples which are to be stored for any length of time. 



Summary 



i. When contrasted with temperatures between 70 and 85 F., 

 temperatures of 87.7 to no° F. caused an appreciable delay in 

 the ripening of green first crop Bartlett pears. 



2. The retardation of ripening was directly proportional to 

 the increased degree of heat within the limits of 87 and 104 F. 



3. The amount of delay in ripening of green first crop Bartlett 

 pears of the different temperatures when contrasted with 70 F., 

 or room temperature, was as follows: 85 F., no retardation; 

 87. 7 , 5 days; 94 F. and 104 F., 13 days. 



4. Second crop Bartlett pears, placed at a temperature of 101 F. 

 and surrounded by a relative humidity of below 50 per cent, 

 remained unripe 4 weeks after similar pears had, become fully ripe 

 at room temperature and humidity. 



5. The relative humidity does not seem to be a significant 

 factor in checking the ripening processes. Its effect is in lessening 

 or permitting wilting, depending upon whether the relative humidity 

 surrounding the fruit is high or low. 



6. The flavor of the pears subjected to those temperatures 

 higher than 85 F. was not normal. There was a slight acidity, 

 and the sweetish taste and juiciness were lacking. 



7. Temperatures above no F. result in a more rapid ripening 

 and consequent breakdown of the tissue than do any of the lower 

 temperatures, down to average room temperatures. 



