ROOT-HAIRS 33 



A good supply of lime is found to increase the number and 

 length of the root-hairs of many plants. 



The hairs are hollow tube-like structures and should not be 

 confused with fine small rootlets. They are outgrowths from 

 the surface of the root (Figs. 72 and 78), and as long as they 

 last are concerned with the absorption of water and various in- 

 gredients in solution from the soil. 



Upon plants growing in the ground the root-hairs are very 

 intimately in contact with the particles of soil and are of so 

 delicate a nature that it is practically impossible to remove a 

 plant without destroying them. 



Ez. 19. — Germinate beans, mustard, oats, barley, and wheat in damp 

 Hannel, and examine the root-hairs on the primary roots. Note their delicate 

 nature, and their position, length, and abundance. 



Although almost invisible they are among the most important 

 organs which plants possess. All the food constituents obtained 

 from the soil and from the various manures applied to the latter 

 are taken in by the root-hairs. By their means plants are kept 

 constantly supplied with water ; their destruction in the process 

 of transplanting or any disturbance of their development and 

 action, such as may be caused by excessive dryness or imperfect 

 aeration of the soil, leads to a deficient water supply and con- 

 sequent withering of the plant. 



