HOW PLANTS TAKE WATER OUT OF THE SOIL 303 



AH food, elements - d tut - eituJtr 



Result of test to show need of mineral foods. 



erals that must be present in small quantities in order 

 that plants may grow. Living matter is a very com- 

 plex substance. We 

 cannot give the exact 

 proportion of its ele- 

 ments, but we know 

 that it contains a large 

 portion of carbon, hy- 

 drogen, oxygen, nitro- 

 gen, and a much smaller 

 portion of calcium, sul- 

 phur, potassium, mag- 

 nesium, phosphorus, so- 

 dium, and chlorine. It 

 would be very easy to 

 show by growing plants 



in water containing solutions of these mineral materials, 

 that they will not live if certain of these ingredients are 

 not found in the water which they absorb. 



How our plants take water out of the soil. If you 

 examine some growing radish or mustard seedlings you 

 find that the roots of the tiny plants are covered with a 



fringe of white, 

 hairlike structures. 

 These are called 

 root hairs. They 

 are long cells pro- 

 jecting from the 

 sides of the root, 

 and are the ab- 

 sorbing organs of 

 the plant. The 



Diagram of a root hair : CS, cell sap ; CW, cell wall ; 

 P, protoplasm ; N, nucleus ; S, particles of soil. 



