Cnapler 8 



VEGETABLE FOODS 



Excess food materials are stored by plants for several pur- 

 poses, chief of which are to furnish future supplies of energy and 

 growth materials, and to start the new generation in the seed 

 with an adequate supply of food. Thus food is stored in those 

 parts of the plant which are the longest lived. Food storage 

 rarely occurs in such transitory organs as leaves, while roots and 

 stems function frequently as storage organs. Underground parts 

 of plants, such as tubers and roots, are especially well adapted 

 for storage because of their protected position. The food stored 

 in reproductive organs (usually fruits and seeds) is used to 

 guarantee the growth of the embryo and to aid in its dispersal ; 

 because of the concentrated amount of food in many such organs, 

 these parts of plants have assumed greater economic importance 

 than vegetative organs, as sources of human food. 



Vegetables in the popular sense include a widely varying 

 number of plant parts; in this chapter the term is used to include 

 the vegetative organs — roots, stems and leaves — used as foods or 

 food accessories. Many fruits of the legume or berry type are 

 considered vegetables in common parlance; these will be con-, 

 sidered in the following chapter. The food value of the true 

 vegetables is often low, because of the large amount of water 

 present in vegetative organs; even so, they rank next to the 

 cereals as a source of carbohydrate foods, which are readily 

 digested and provide a high energy content. • Proteins and fats 

 occur in some vegetables, but in negligible quantities. Minerals 

 and vitamins are often present in considerable quantity, and the 

 bulky cellulose tissues give valuable roughage to our diet. 



Roots Used as Food 



From earliest times, roots and underground parts of plants 

 have played an important role in sustaining human life. Such 



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