The Food of Plants 



that are needed for 

 building proteins, rapid 

 growth in a plant is not 

 possible. 



The proteins can be 

 made in any living part 

 of the plant ; but the 

 materials of which they 

 are built are most abun- 

 dant in the leaves, and 

 they are manufactured 

 in larger amounts in the 

 leaves than in other 

 parts. From the leaves 

 they may be carried to 

 other parts of the plants 

 for storage or for the 

 immediate use of the 

 cells in those parts. 



Materials necessary 

 for life and manufacture 

 of food in green plants. 

 Ten chemical elements are necessary for the life and 

 growth of a green plant. 1 Of these elements, oxygen, 

 carbon, and hydrogen are used in largest amounts. 



The oxygen used in respiration is secured chiefly from 

 the air; that used for building purposes comes from 

 water and carbon dioxid. The carbon is obtained in 

 the carbon dioxid taken in from the air. The hydro- 



FIG. 35. The gardeners are appropriating 

 the food that the plants have made for 

 themselves. 



1 These ten elements are carbon, oxygen, hydrogen, nitrogen, sulfur, 

 ohosphorus, potassium, calcium, magnesium, and iron. 



