Abscission of Flowers and Fruits of the Apple 109 



31. Leaves on detached spurs that bear fruit remain turgid for some 

 time, since they can draw water from the fruit. Apples with many 

 seeds lose less water than those with few seeds. 



32. Sap from fruit with few seeds depresses the freezing point less 

 than does sap from many-seeded fruits. 



33. Unsymmetrical fruits resulting from imperfect fertilization are 

 more frequent in fruit that has dropped than in fruit that remains on 

 the tree. 



34. Short-stemmed fruits, which are developed from central flowers, 

 have fewer seeds on the average than do long-stemmed fruits. 



35. Fruits with short stems usually attain a greater weight than fruits 

 with long stems borne on the same spur, even tho the latter ma}' contain 

 more seeds. 



36. Fruits borne singly on vigorous spurs may attain a weight as great 

 as that of the larger apples from spurs bearing two fruits, even tho the 

 latter may have a greater seed content. 



37. The average number of seeds in a normal apple is greater than 

 in fruit that has been stung by aphids. Apples attacked by aphids remain 

 attached to the tree even tho no seeds are formed. 



38. Fruits stung by aphids may develop a water-cored condition. 

 Such a condition is also caused by over-abundant water supply. 



39. Removal of the fruit from its stem induces the formation of an 

 absciss-layer between the stem and the spur, which results in the shedding 

 of the stem. The shorter the stem, the more quickly is the absciss-layer 

 formed. 



40. Fruits coated with vaseline or grafting wax fall after one week. 



41. Detached fruiting spurs kept in a receptacle with a saturated 

 atmosphere lose their apples after several days; similar spurs kept in 

 a dry atmosphere retain their fruit. 



42. Vaseline-coated fruits on spurs with their stems standing in water 

 fall after eight days; fruits similarly treated on spurs not having access 

 to water remain attached to the spurs. Untreated fruits on spurs standing 

 in water also remain hanging. 



GENERAL DISCUSSION 



The results presented in the foregoing pages emphasize the importance 

 of vigor, more especially the vigor of the individual spur, as a factor 

 in fruit setting. As compared to weak spurs, the previous season's growth 

 of vigorous spurs is longer, the new spur growth is heavier, the leaves 

 are larger and more numerous, there are more flowers to the spur, the 

 diameter of the conducting tissue is greater, and the weight of the lateral 

 s])ur growth is greater. 



2.27, 



