PLANT PHYSIOLOGY 



255 



The following diagram also represents the series of changes : 



ATMOSPHERE 

 NITROGEN (N) 



Reducing //by \Nodule 

 bacteria/ /^.'^Is/.'tric \bacterla, 



NITRIC ACID (HNO3) 

 NIXRATES (KNOo 



csoiy 



Reducing 

 Jjacteria 



PLANT 

 PROTEiN 



NITROGJENy 



Oxidising svXcYCM} /i 

 bacteria<<V> 



<) ^ 

 AMMONIA (NH3)^< ^eath and ba/teria ANBIAL PROTEIK 

 (Soil) 



Animal food 

 ^etaqollaaa) 



Bact 



r© 



Bacteria 



/^ Katabollsm 



UREA, etc. J:^ 

 00 (NH2)2 

 (Soil) ^ 



RESUME 



Plants, like animals, as living organisms, utilize organic food 

 consisting of carbohydrates, fats and proteins, for the liberation 

 of energy necessary for the life process. In plants, however, 

 the net result, or the predominating reaction, is not to expend 

 energy but to conserve or store it. The process that produces 

 this result is photosynthesis. By the photosynthetic action 

 of green plants chlorophyll bodies or chloroplasts, together 

 with the green pigment chlorophyll, utilize the kinetic energy 

 of sunlight for the synthesis of complex organic compounds 

 from the carbon dioxide of the air and water of the air and soil, 

 at the same time setting free oxygen which is given off into the 

 air. In these complex compounds the used kinetic energy of 

 the sun is stored as potential energy. 



The probable direct result of photosynthesis is the carbohy- 

 drate glucose. This photosynthesized glucose is converted by 

 metaboUc changes into more complex carbohydrates, e.g. cane 



