A YEAB IN SCIENCE 5 



Exercise 56. Roots. 



Object: A study of the kinds and functions of roots. 



Apparatus 



Lupine seedlings Carrot 



Wheat seedlings Dahlia roots 



Directions: Examine the root of a lupine. Is there 

 a single branch, or are there several of equal size arising 

 from the same point? These are called the primary 

 roots. The roots growing from the primary are called 

 the secondary roots. Have they any definite arrange- 

 ment on the single primary root of the lupine? At 

 what angle do they grow from the main root? What 

 function of the root does this suggest? With the 

 lupine compare a carrot, radish, beet, or dandelion root. 

 How do the latter differ from the lupine? What other 

 function does this suggest for some roots ? 



Examine the roots of some grain seedlings. Do they 

 have a single primary root or many fibrous roots? 

 Make observations similar to those made on the lupine 

 root. What difference do you observe? Compare the 

 dahlia root with those of any grain. There are two 

 principal kinds of underground roots. Those growing 

 with a single main branch are called primary tap roots, 

 while those with several main branches are called mul- 

 tiple primary or fibrous roots. An example of the tap 

 root is the lupine ; of the fibrous roots, the grains. 

 When the tap root is used for food storage as in the 

 radish, it is called a fleshy tap root. When the fibrous 



