84 LABORATORY MANUAL 



two plants under the same conditions of light, moisture, 

 and temperature. Do not change these conditions until 

 the experiment is completed. 



Note and record results as you did with the seeds. 

 At the end of a week do you notice any differences in 

 the two plants? What does this indicate? 



Exercise 55. Exchange of Gases in Respiration. 

 Object: To determine the gases exchanged in res- 

 piration of plants. 



Apparatus 



Wide mouth bottles Pine splinter 



Green plants Stoppers 



Lime water 



Directions: Fill three bottles to the depth of one- 

 half inch with water. Into two of the bottles place 

 a few shoots of green plants. Close the three bottles 

 tightly with rubber stoppers and place them in a 

 dark room until the next recitation. What gas was in 

 the bottles when the experiment was set up? Is this 

 same gas present in the bottles containing the green 

 plants at the end of the experiment? In the bottle 

 without plants? To determine this, insert into one of 

 the bottles with plants a lighted splinter. What is the 

 result? In the same manner insert a lighted splinter 

 into the bottle having no plants. What is the result? 

 What do these results indicate? Test the gas in the 

 third bottle with lime water. What is the effect ? From 

 these results what gases are exchanged in respiration 

 of plants? 



