SIGNIFICANCE AND EARLY IDEAS 3 



rials, by cutting or otherwise interfering with the movement 

 of solutes and perhaps water, though chiefly the former, 

 one can greatly alter behavior of this sort, especially of 

 regeneration phenomena. It is true that utilization in its 

 broader sense has a distinct role to play in distribution. 

 Therefore in one sense behavior partly determines distribu- 

 tion and yet, in the last analysis, distribution also controls 

 behavior. 



It is rather clear that a knowledge of how materials move 

 about within a plant and what conditions determine this 

 distribution are of fundamental importance to one attempt- 

 ing to explain many types of plant behavior. Considering 

 its importance it would seem that much attention would 

 have been directed toward a solution of the problems of 

 translocation. Problems of major importance obviously 

 involve the following: The tissues concerned in trans- 

 location, the mechanism of transport, factors determining 

 the direction of transport, and factors influencing the rate 

 of movement. It is true that a great deal of attention has 

 been given to the problems of water movement within 

 plants, but it is rather surprising how little attention, 

 either in the general Uterature or in textbooks, has been 

 given to solute movement. Lecomte, in 1889, stated that 

 no problem is more important to the life of the plant than 

 translocation and none has been more neglected by bota- 

 nists. But neither his own valuable contributions nor his 

 statement concerning the importance of the subject served 

 to stimulate much interest in the subject. 



The lack of attention given to these problems may have 

 been due in part to a failure to appreciate that they are 

 problems. In fact until recently it has been assumed that 

 the tissues concerned in the movement and the method of 

 movement, particularly that from the roots to the leafy 

 parts, and the factors influencing the rate of movement 

 were rather fully understood. 



2. Older Ideas as to Tissues Concerned in Upward 

 Transfer. — The absorption of large amounts of water by the 

 roots, its passage through the wood to the leaves, and its 



