I50 OUTLINES OF PLANT LIFE. 



EXERCISE XXXVI. 



To show the evolution of heat during respiration. 



Take three-fifths the amount of dry wheat required to fill two 3-inch 

 flower pots ; swell in water over night ; rinse one half in 5 per cent 

 formalin ; kill the other by boiling in water for five minutes. Stop bottom 

 hole in pot with a cork ; fill one with dead, the other with living seeds, 

 and bring the two to same temperature by running water through the 

 dead and hot one. Insert a thermometer in the center of each mass of 

 seeds ; place both under one box or bell jar. Observe changes of tem- 

 perature for two days.* 



209. Contrast between respiration and photosynthesis. 



— Since the processes of respiration and photosynthesis in 

 green plants are so frequently confused, a contrast is here 

 drawn between them. 



Respiration. Photosynthesis. 



Occurs in all living cells. Occurs only in green cells. 

 Indifferent to or retarded by Requires light. 



light. 



Consumes organic matter. Produces organic matter. 



Produces carbon dioxid. Consumes carbon dioxid. 



Consumes oxygen. Produces oxygen. 



Sets free energy. Stores energy. 



210. Other destructive changes. — Besides those constitut- 

 ing respiration, a considerable number of other destructive 

 changes occur, which are not so closely connected with the 

 vital functions of the plant. They result in the production 

 of substances which are of no further use in nutrition and 

 only of incidental value for any purpose. Such substances 

 may be stored in some out of the way place ; or put into such 

 parts as are transient, so that, by the loss of these parts, the 



* Compare thermometers previously to see that they register alike ; if 

 not ascertain the correction. Greater differences in temperature of seeds 

 will be observed if pots are surrounded with cotton batting. 



