26 



TRANSLOCATION IN PLANTS 



or storage tissues below. The reason for the defoHation was 

 to eliminate the possibility of the utihzation of food manu- 

 factured or stored in the leaves of that region. Growth, 

 as measured by increase in length of the shoot, was most 

 commonly taken as a measure of solute movement, though 

 in a few instances the fresh weights, dry weights, sugar 

 contents, and freezing-point depressions were also taken as 

 criteria. Measurements were usually made at a period 

 from one to three days after the beginning of the experi- 

 ment, though in a number of cases measurements were 

 continued up to periods of six to fifteen or more days. 

 Representative data are summarized in Table 4. 



From these data it is evident that growth is very weak 

 in shoots that are both defoliated and ringed. The growth 

 in the other shoots was always distinctly better, but the 

 relative order of their growth depended on the length of 

 shoot and therefore on the number of leaves above the 

 ring, or the length of shoot defohated, and also in part 

 upon the number of leaves below the ring. For example, 

 if that part of the shoot bearing leaves above the ring is 

 long, the growth of this part is much greater than if the 

 length, and therefore the number of leaves supplying the 

 food, is less. If the defohated region is short, and a ring 

 separates the region from the leaves below, growth may be 



