CHAPTER XXIII 

 STORAGE AND TRANSLOCATION 



Find where nature moves. 



— Pope. 



In the leaf factory, where the initial synthetic products are 

 made, large accumulations of foods would hinder the action and 

 operation of the photosynthetic mechanism. Just as in any 

 ordinary factory the finished products are removed from the 

 vicinity of the machinery at the earliest opportunity to make 

 room for those continually being made, likewise in the leaf factory 

 there must be some arrangement for taking out of the leaf the 

 manufactured materials. These substances are removed to places 

 where they may be immediately used up in the metabolic processes 

 of the plant or, if the plant is making much more food than it is 

 using at the time, the surplus is stored. The requisite conditions 

 for storage are simply that the plant manufactures more of a 

 given material than it can immediately utilize. 



Temporary and Storage Products. — Many substances produced 

 within the cell are temporary products, which are very quickly 

 used inside of the cell, or they may be transition products which 

 are rapidly transformed into something else. Some of the simpler 

 carbohydrates, the amino acids, fatty acids, etc., as we have 

 previously seen, are for the most part built up quickly into other 

 compounds; although what is a temporary product in one plant 

 may be a storage product in another. 



Regions of Storage.— In the higher plants, owing to their 

 particular methods of growth, large quantities of food may be 

 stored in special organs adapted for the holding of such reserves. 

 These storage organs are generally drawn upon for the growth of 

 the plant at a time when food cannot be manufactured or for the 

 reproduction of the plant. The organs chiefly concerned with 

 the storage of food are: 



1. Stems. 



a. normal stems— cortex, rays, pith, and wood parenchyma. 



b. specialized stems— tubers, rhizomes, bulbs, and corms, 



2. Roots. 



3. Seeds. 



4. Fruits. 



277 



