METABOLISM DIGESTION TRANSLOCATION GROWTH 2 13 



The carbohydrates and other products which are manufac- 

 tured in the green parts of the plant must be transferred to 

 other parts of the plant for immediate or future use, except in 

 those plants in which the leaves serve for storage. Therefore, 

 practically all of the stored materials found in fruits, seeds, 

 tubers, bulbs and fleshy roots have been manufactured in the 

 leaves and transferred to these parts for storage. We have 

 called attention to the translocation of the various minerals. 



Assimilation. This is a process which very naturally fol- 

 lows digestion and which precedes growth. It is the transforma- 

 tion of true foods of the various kinds into living protoplasm. 

 Foods must be assimilated by and become a part of the living 

 protoplasm before they can be used for growth or for repair. 

 Assimilation will not be thoroughly understood until we have a 

 thorough knowledge of the chemistry of living protoplasm and 

 of the compounds from which it is developed. 



Reserve Foods and Storage. Although the plant makes its 

 own true foods from the raw materials which it secures from 

 the soil and air, it does not necessarily use them immediately. 

 We have already learned that foods may be stored in stems, roots, 

 leaves and seeds to be used by the plant at some future time. 

 The character of this stored food, the absence of undesirable 

 plant products and the character of the plant structures are im- 

 portant factors in determining the value of the plant as a food 

 for man arid live stock. Carbohydrates, fats, oils and proteins 

 are the most common forms of storage products found in plants 

 (see Chapter XI). These plant products must undergo diges- 

 tion before they can be assimilated and used for the growth 

 of the plant. 



