EXERCISE 42 



Problem. What is the structure of the absorbing part of a root ? 



What to use. Flax or radish seeds ; blue or green blotting paper ; petri dishes, Syracuse dishes, or 

 any convenient flat containers; magnifier and microscope. The pocket 'garden used in Exercise 36 

 will serve very well to grow the seeds. 



What to do. Place seeds on moist blotter in container ; cover and leave for two days. 



Examine the roots of the seeds (i) with the unaided eye, (2) with a lens, and (3) under the com- 

 pound microscope, low power. 



Record. Make a large drawing of what you see in each of the above cases ; note the location and 

 relative size of the " root hairs." 





Questions. 1. How many cells are there in a root hair? 



2. What is the relation between the root hairs and the skin cells ? 



3. Estimate the size of the root hair. 



4. What is the form of the root hair? 



5. What is the advantage to the plant of these outgrowths on the root ? 



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