Nature-Study Agriculture 



(Fig. 4), the outer walls of which are very thin. (Exp. 

 3.) It is into these delicate tubes that most of the water 



FIG. 5. 



Cross section of a small root, magnified, showing root hairs. 

 (The black specks are soil particles.) 



Their 

 importance 



How they 

 grow 



"Root 

 pasturage " 



Why root 

 hairs are 

 hard to find 



and dissolved food material first finds its way. There 

 are so many of these root hairs that their total surface 

 is from five to ten times as great as the water-receiving 

 surface of the roots themselves (Fig. 5). The root hairs 

 die as the root grows longer. They never live more 

 than a few days, and they never develop into roots. 

 New root hairs grow out continually, just back of the 

 growing ]5oint. 



The term " root pasturage " is sometimes applied to 

 the work of the growing roots, as they make their way 

 between soil particles and constantly send out new root 

 hairs to absorb food materials and water from new soil 

 areas. We seldom see the root hairs, for although they 

 are large enough to be easily visible, most of them are torn 

 off when we pull up a plant even from loose ground. A 

 sort of mucilage which they produce causes them to cling 

 closely to the soil particles. 



