The Respiration of Plants 87 



time until it loses its colour, and after cooling place germinating seeds 

 within the tube. Observe after half an hour and tell what gas has been 

 given off by the seeds. 



Prof. Farmer uses methylene blue to show gas exchange in photo- 

 synthesis (see p. 94). By using the two colours, the exchange of gases in 

 respiration is well shown. 



In this exchange, the important thing to remember is that 

 in respiration, the oxygen in uniting with carbon releases 

 energy. This energy is used by the plant in doing work, 

 that is, in the making of food, in growth, and reproduction. 



While the terms respiration and breathing are frequently 

 used interchangeably, breathing in animals involves expanding 

 the chest muscles and inflating the lungs, for which there are 

 no corresponding processes in plants. You can see an animal 

 breathe, but you can see neither an animal nor a plant respire. 



