384 GENETICS IN RELATION TO AGRICULTURE 



fruits, Baur states that there are varieties of eggplant which occasionally 

 bear tomato-shaped fruits even when not grafted, and that Daniel 

 probably used such a variety. Again Daniel and Elder have reported 

 experiments tending to show that the seedlings of scions exhibited an 

 influence of the stock. Baur is inclined to think that accidental cross- 

 pollination must explain such cases. But Daniel has recently reported 

 similar results when working with different varieties of beans. In this 

 case, however, there is the possibility that the seedlings of the scions 

 and the seedlings used for comparison, which were from ungrafted plants, 

 belonged to different pure lines. Thus in some such simple manner all the 

 supposed cases of transference of morphological characters may be 

 explained. 



Regarding the actual transference of the chemical constituents of the 

 tissues from stock to scion and vice versa, the results of experiments 

 differ with respect to different plant ingredients. Thus, according to 

 Guignard, glucosids do not pass from one graft component to the other 

 when the two contain different kinds of glucosids, and the glucosids 

 present in plants are apt to differ unless the plants are closely related. In 

 graft-symbionts whose components belong to different species, Guignard 

 thinks that each component tends to retain its own chemical properties. 

 On the other hand, Meyer and Schmidt found that alkaloids such as 

 nicotine will pass from a tobacco scion into a potato stock. This is a 

 promising field for future investigation. 



