40 



TRANSLOCATION IN PLANTS 



were rinsed out frequently with distilled water, but this 

 also had no measurable effects. In still other instances 

 the xylem was cut and the phloem left in place but cut and 

 held in its normal position by a splinter of wood. These, 

 as shown in Table 6, usually showed practically the same 

 behavior as the ringed ones. Occasionally, however, they 

 elongated somewhat more during the first day. This 

 latter was probably due to the fact that completely severed 

 shoots no longer had to compete with the tissues below for 

 their water supply. The ringed shoots were handicapped 

 in their competition through their having a low content of 

 osmotically effective solutes (see Sec. 7). 



In a few sets sugar analyses were made, typical examples 

 of which are presented in Table 7. 



Table 7. — Comparative Effects of Cutting the Xylem or Phloem 

 ON Growth, Water Content, and Sugar Content of Defoliated 



Shoots 



For the Philadelphus set, ^, it is obvious that sugar was 

 deficient in the shoots of the ringed stems and that this 

 lack of sugar probably accounted for the poor growth. 

 This set received very little light before and during the 



