16 
LABORATORY EXERCISES 
EXERCISE 16 
RESPIRATION 
Place a half cup of soaked peas in a wide-mouthed eight ounce 
bottle. In another, place the same amount of dry peas. Cork both 
bottles tightly. Then allow them to stand in the room for forty- 
eight hours. At the end of this period test the air in each bottle 
for carbon dioxide. What is the result? Test for oxygen. (See 
Appendix.) What is the result? What is the origin of the carbon 
dioxide which you find in one bottle? What became of the oxygen 
in the same bottle? What change has been taking place in the 
peas in this bottle? For what purpose is oxygen needed in this 
process. What is respiration? (See Waggoner, Page 69.) Of 
what use is it to a plant? 
(Note —Prepare seeds for growth of root hairs. See Exercise 
18.) 
EXERCISE 17 
ROOTS 
The collection of the roots to be used in this exercise may be 
made by individuals or by the class as a whole. 
I. Field Study. Collect roots of the following types: 
1. Soil roots, a. Fibrous, the grasses, b. Storage, the sweet 
potato or dahlia, c. Woody, shrubs and trees, d. Tap, the rag¬ 
weed, carrot, parsnip, etc. 
2. Air roots. The trumpet vine {Tecoma radicans). 
3. Water roots. The duck weed, or other common floating 
water plants. 
II. Laboratory Study. Arrange an exhibit of the roots which 
are collected. Attach a label bearing the name to each. List and 
state briefly the characteristics of each. This may be done in a 
tabulated form as follows. 
