CHAPTER VI. 



WORK OF ROOTS IN ABSORPTION OF WATER AND 

 FOOD FROM THE SOIL. 



62. Absorption of water and food sub- 

 stances from the soil. Land plants ab- 

 sorb water and food solutions chiefly 

 through the root hairs. In the study of 

 seedlings we observed the form of the root 

 hairs and their position on the roots. They 

 are very slender, long cells developed in 

 great numbers over the surface of the root a 

 little distance back from the tip of the root. 

 The root hairs are not permanent. As the 

 root elongates, new root hairs are formed, 

 while the older ones farther back on the 

 root die. Thus the root hairs are fresh 

 and in good condition for their work of 

 absorption. 



63. How the root hairs absorb water 

 from the soil. Each root hair is a plant 

 cell (paragraph 3) which is very much 

 elongated. It is formed by the lateral 

 elongation of one of the cells of the skin or 

 epidermis of the root. The outer part or 

 boundary of the root hair is its cell wall. 

 It is thin and white. Inside of the root 

 hair is a granular, whitish, slimy substance. 

 This is the living substance of the cell, and 

 is called protoplasm (paragraph 5). It is the 



living protoplasm in the root hair which en- Root JJV^ bcforc 

 ables it to take up water and food solutions. ^ r a c f cn r t . SuSSU^ 



39 



