ON THE TOMATO 



it is absolutely essential to the leaf system above 

 it, is also very largely dependent on that system. 



In other words, there is the closest reciprocal 

 relation between root system and leaf system. 



This relationship, which many orchardists over- 

 look, I have long recognized and have repeatedly 

 referred to. But the case of the tomato on the 

 potato root emphasizes the lesson in such terms 

 that no one can ignore it. With this illustration 

 before us, we can scarcely doubt that the root 

 system of any stock on which a foreign top is 

 grafted (as is the custom in most orchards) is 

 modified in some measure by the cions it bears. 

 The foreign leaves cannot supply precisely the 

 same quality of nourishment to the root that leaves 

 of its own kind would have supplied. 



In the main, no doubt, the protoplasm of the 

 root assimilates the nourishment that comes to it, 

 and makes it over into its own kind of protoplasm. 

 But we know that the flesh of animals varies in 

 quality with the food given the animal, and we 

 cannot well doubt that the protoplasm of the root 

 of a plant must similarly be modified by the 

 character of its food. 



And this line of thought suggests the further 

 possibility that when more cions than one are 

 grafted on the same branch or on the same trunk, 

 there must be a certain intermingling of the sap 



[141] 



