INOCULATION 
259 
have them help plants to an appreciable degree, there must be 
many of them. It has been found possible to place them in 
the soil artificially, a process called inoculation. This is 
done either by wetting the seeds with water containing the 
bacteria, or by putting them into the soil in some other 
manner. Care should be taken to secure only pure cultures 
(see page 313) and to have them fresh. By the use of 
cultures a soil properly inoculated will not only produce 
larger crops of leguminous plants, but its quality is also 
improved for crops which follow them, as explained above. 
SUMMARY 
The root is the part of the plant that grows in the soil to 
gather water and food materials for it, to hold it securely, and 
to store food for it. Roots have many forms, the primary 
or tap root and the fibrous roots being the extremes. Small 
roots have a root cap to prevent injury to their tips, and 
root hairs to increase their absorbing surface. There are 
specialized roots for special purposes, such as aerial roots 
for support and for gathering water. Adventitious roots 
are those that grow on “ slips.” Roots form an important 
part of man’s food, and food for his animals. 
QUESTIONS 
What is the root? What does it do for the plant? Describe the 
structure of a tap root. How do fibrous roots differ from a tap root? 
In which kind of roots is most food stored? What use does the plant 
make of this stored food? What use does man make? What kinds 
of food are stored in roots? 
REFERENCES 
Bergen, Foundations of Botany, pages 62-129. 
Bergen and Caldwell, Practical Botany, pages 5-16, 24-38. 
Conn, Biology, page 112. 
