HOW FOOD IS USED BY PLANTS 333 



337. Food storage. When the food is in solution and is 

 therefore capable of being transferred from place to place 

 within the plant, it may be disposed of in one of three ways : 

 it may be used immediately for repair and growth, or it may 

 be used in respiration, or it may be stored. 



When food is stored it is usually changed into an insoluble 

 form again. For example, sugar is commonly changed into 

 starch, though there are cases in which sugar itself is stored. 

 Food may be stored in almost any part of a plant, but usually 

 it is stored in large quantities only in much-thickened parts. 

 Examples of thickened storage parts are the potato, carrot, 

 parsnip, radish, onion, beet, sweet potato, various bulbs and 

 tubers, fleshy fruits, and seeds. Very often food is deposited 

 in the roots and other underground parts of the plant. In 

 these cases the food which is made and stored during the 

 summer commonly serves for the plant's growth during the 

 earlier part of the following season. 



The large amount of food which is brought together within 

 a small space makes these storage organs of plants an im- 

 portant article of food for men and animals. The starch and 

 proteins stored in wheat are two of the valuable things in 

 wheat, and this is the most important single food for the 

 Caucasian race. In the Orient China, Japan, India the 

 most important food storehouse is the rice grain, and a very 

 large part of the human race is dependent upon it for their 

 principal food. Rye flour is used for bread in some European 

 countries. Beans and peas contain starch and more protein 

 than almost any other common vegetable food. They are 

 therefore particularly valuable as a substitute for meat in hot 

 countries or in places where meat is scarce. 



Corn and oats are used for human food, but not to so 

 great an extent as some of the other grains. They are usually 

 fed to animals, which may then be used as food. A few 

 seeds, such as the castor bean, cotton seed, and corn, store a 

 good deal of fat and are often pressed to give an edible or 



