UPWARD TRANSPORT OF ORGANIC MATTER 



39 



pressed onto the cork. Data from several sets of experi- 

 ments are available in the earlier paper (1925). Similar 

 data from experiments not previously reported are pre- 

 sented in Table 6. 



Such data have been obtained with many kinds of woody 

 plants and several hundred sets of shoots, in which the 

 effects of cutting the xylem and of cutting the phloem 

 and cutting neither have been compared. The data have 



Fig. 6. — Photograph of typical set of shoots of Rhus, showing relative amounts 

 of growth about 6 days after beginning of the experiment. 1, check; 2, phloem 

 cut; 3, xylem cut. 



uniformly shown that growth is markedly checked when the 

 phloem is cut, whereas, when the xylem is cut and part of 

 the phloem is left intact, growth is very much greater and 

 approaches more nearly that of the check shoots. A 

 photograph of a representative set of Rhus shoots is shown 

 in Fig. 6. 



To ehminate the possibility of transfer of solutes through 

 the water and across the gap between the cut ends of the 

 xylem, several experiments were set up in which the ends 

 from which the solutes might be expected to issue were 

 sealed with hot paraffin, but this had no influence on the 

 growth of the shoots above. In other instances the tubes 



