INFLUENCE OF STOCK ON CION 161 



may it affect the keeping quality. The Duchess apple 

 when top-worked on the Ben Davis will keep from four 

 to six weeks longer than the same apple worked on the 

 common stock. 



The cause of these varied influences may be attributed to 

 two sources namely, mechanical and physiological dis- 

 turbances. This can more easily be understood when we 

 think of the cell as being the plant unit. Each cell performs 

 its own functions. Theoretically the cells of the stock 

 perform all those functions characteristic of the stock, 

 up to the point of the union. Then the cells of the other 

 co-parent take up the work from that point and modify 

 the processes, in accordance with their own peculiar char- 

 acter. While there is a rather wide division of labor in 

 the functioning powers of the cells of the different organs, 

 there is a more or less definite protoplasmic organization 

 throughout the entire plant tissue. Certain cell sub- 

 stances such as sugar may be differently affected by the cells 

 of each of the co-parents. If the cells of the stock are 

 capable of developing a higher sugar content than the cion, 

 presumably the cells of the latter will not reduce it, hence 

 an increase or decrease in the acid or sugar content is in- 

 fluenced by the stock. Of course this is relatively a very 

 small amount and were it not the case the entire purpose 

 of graftage would be lost. 



In the case of dwarfed stock the cause is more mechanical. 

 The root system of the slow growing plant is incapable of 

 supplying sap as fast as the more rapidly-growing top 

 demands, hence a reduction in size. Conversely the de- 

 mands of the actively growing top stimulate the root 



