86 



BOTANY 



tender growing point of the root. Just beneath the root cap is a collection 

 of tiny, thin-walled cells. At that point the cells are engaged in dividing 



into new cells very rapidly indeed. This 

 is the point of most rapid growth in the 

 root. 



How the Root takes in Water. — That 

 the root of a plant is attracted by water 

 and is also stimulated by gravity has 

 been already shown. Let us now attempt 

 to solve the question of how the root 

 takes in water. To help us in obtaining 

 our answer we should examine the pocket 

 gardens which we planted a few days previously. Look carefully at the 

 tiny roots of barley or corn, and you will find that they are covered in places 

 with what looks like a fuzzy growth. These hairlike structures are called 

 root hairs. What is the color of the root hairs to the naked eye ? Where 



The end of a growing root, tipped and 

 protected by the root cap; g, the 

 growing point. (Considerably mag- 

 nified.) 



Root hairs of barley. The white appearance of the roots is due to these organs of 



absorption. 



are the root hairs largest ? Where are they longest ? Where are they most 

 abundant? Try giving your pocket garden more water; what is the effect 

 on the root hairs? Can you get a similar result by cutting off the water 

 supply of the roots ? Do root hairs ever disappear after once coming out 

 on the root ? 



Structure of a Taproot. — To understand fully the relation of 

 the root hairs to the rest of the root, it will be necessary for us to 

 examine some large, fleshy root (a taproot), so that we may get 



