CHAPTER V 



CARBON 



HOW PLANTS FEED 



Learned men have been searching for many centuries 

 that they might discover the elements which form the 

 world. 



Up to the present time between seventy-five and 



eighty have been found 

 in the soil, the rock, and 

 the air; butstrangeasit 

 may seem, only fifteen 

 of this number are 

 found in plants and ani- 

 mals, ten of which arc 

 absolutely essential to 

 the growth of plants. 



Where plants get 

 their food. There are 

 just two sources of 

 plant food : the soil and 

 the air. The young 

 plant beginning its life 

 obtains its first food 

 from the seed. With 

 this food it starts its 

 roots into the soil and 

 its stems and leaves in- 

 to the air. Henceforth 

 both roots and leaves 

 will gather food for 

 further and future 

 growth. 



WATER AND 

 MINERAL 

 SUBSTANCES 



'NITRATES * 

 HOW PLANT FOOD GETS INTO THE SOIL 



Carbon is taken in through the stomata, or 

 mouths, on the underside of the leaf. All 

 the mineral elements and the nitrates are 

 in solution in the water and pass in this 

 way into the plant through the root hairs at 

 the tip end of the growing root. Laterthis 

 same water passes out of the leaves as 

 vapor 



