THE METABOLISM OF PLANTS. 



327 



INCOME. 



Energy. 



Rays of light absorbed by chlo- 

 rophyll. 

 Heat. 



EXPENDITURE. 



Matter. 



Excreted substances (organic or 



inorganic). 



Reproduction (spores, seeds, etc.). 

 Other losses (leaves, fruits, bark, 



etc.). 



Energy. 



Constructive metabolism. 



Growth. 



Heat. 



Motion (in some cases). 



Light 



Electricity 



Potential energy (when organic 



matter is excreted or thrown 



off). 



BALANCE in favour of plant. 

 Matter. 



Organic matter, including 

 Tissues. 



Reserve-materials. 

 Unexcreted waste-products. 



Energy. 



Potential energy represented by 

 the organic matter. 



In the case of a plant which does not possess chlorophyll 

 the items must be altered as follows. 



INCOME. 



Matter. 

 Food. 



Inorganic salts. 



Organic matter. 



Water. 



Free oxygen (in most cases). 



Energy. 



Potential energy of organic food. 

 Heat. 



EXPENDITURE. 



Same as above, except that no 

 free oxygen is given off. 



BALANCE in favour of plant. 

 Same as above. 



