COURSE OF FOOD DISTRIBUTION 



167 



diameter of branches, trunk and roots; but by the beginning of 

 summer, or even in May, much of the food is being stored in 

 roots and trunks. 



By August growth has almost ceased in most woody plants, 

 and the bulk of the food 

 made thereafter is stored 

 in branches, trunk, and 

 roots for use during the 

 winter to a certain extent, 

 and for resumption of 

 growth in the spring. In 

 accordance with this the 

 flow of the food would 

 be up as well as down in 

 the first part of the period 

 between the appearance 

 and fall of leaves, and 

 chiefly down for storage 

 after the elongation of the 

 branches and the growth 

 of fruit has practically 

 ceased. 



Most of the reserve food 

 is stored in the roots and 

 trunk, and in the spring 

 the larger part must as- 

 cend where growth and 

 fruitage is going on in 

 the crown, and where 

 cambial activity is first 

 awakened. The sieve tubes which are empty during the 

 winter can be filled by these ascending currents, and in 

 most instances the tracheal tubes are also pressed into service 

 and carbohydrates, chiefly as sugar, and proteids and amides to 

 a certain extent, are poured into, them from their place of storage 

 in the xylem and phloem parenchyma and medullary rays. 



Fig. 93. — Diagram showing how, in Indian 

 corn, the food from the upper and lower leaves 

 finds its way into the ears. 



