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Bulletin 393 



TABLE 48. Depression of Freezing Point by Sap from Fruits with Varying 

 Numbers of Seeds, Weights of Spurs, and Weights of Fruits 



Relation between formation of seeds and symmetrical development of fruit 

 It may be of interest in this connection to record observations regarding 

 the symmetry of fruits. MuUer-Thurgau and Ewert give figures in which 

 the amount of flesh of the fruit is more or less proportional to its seed 

 content. If the seeds are confined to one side of an apple, only that 

 side will be fully developed while the other side will be much smaller. 

 Such unsymmetrical development is found in a high proportion of the 

 fruits that are lost during the June drop. Comparatively few of the normal 

 apples — those free from insect, disease, and other blemishes — which 

 remain on the tree are one-sided, altho mature fruits with one or more 

 of their cavities seedless are frequently found. These observations can 

 be explained in the following manner: 



As has just been shown, fruits with many seeds, or with a high seed 

 value, apparently have denser sap than few-seeded fruits. Such many- 

 seeded fruits can therefore exert a greater pull on the sap flow. If the 

 fruit is borne on a weak spur, the seeds play a very important part in 

 obtaining sufficient food and water because the sap must pass thru a 

 poorly developed conducting tissue. If a fruit with a seedless cavity 

 happens to develop on a weak spur, the side without seeds suffers first 

 and falls behind in growth. Sooner or later the poorly pollinated fruit 

 on the weak spur drops, and hence many of the drops are one-sided. 

 Poorly pollinated fruit that remains on the tree is usually borne on 

 vigorous spurs. Such spurs are generally provided with good conducting 

 tissue which can supply abundant sap with comparatively little stimu- 

 lation such as is afforded by seeds. The influence of the seeds in fruits 

 developed on strong spurs is therefore only a secondary influence, and 



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