CHAPTER II 

 THE ORGANIC COMPONENTS OF PLANTS 



FROM the standpoint of their ability to synthetize synergic 

 foods (see page 2) from inorganic raw materials, plants may 

 be divided into two types; namely, the autotrophic, or self-nour- 

 ishing, plants, and the heterotrophic plants. 



Strictly speaking, only those plants whose every cell contains 

 chlorophyll are entirely self -nourishing; and some parts, or 

 organs, of almost any autotrophic plant are dependent upon the 

 active green cells of other parts of the plant for their synergic food. 

 Furthermore, if the term is used in a very wide sense, green plants 

 are more than self-nourishing, they really nourish all living things. 

 But the general significance of the term " autotrophic plants " is 

 apparent. 



" Heterotrophic plants " must, of necessity, get food, either 

 directly or indirectly, from some other plant which can synthetize 

 synergic foods or, in a few cases, from animal organic matter. If 

 they do this by feeding upon the organic compounds of other living 

 organisms, they are known as " parasites "; while if they secure 

 their organic food from the tissues or debris of dead organisms, 

 they are called " saprophytes." The heterotrophic plants are 

 chiefly the bacteria and fungi; although a few seed-plants are 

 devoid of chlorophyll or have nutritive habits similar to those of 

 the non-green plants, and a few species are semi-parasitic or semi- 

 saprophytic. 



It is obvious that the metabolic processes of the autotrophic 

 plants are very different from those of the heterotrophic type of 

 plants. These differences constitute a most interesting field of 

 study for plant physiologists. But the nature of the chemical 

 compounds themselves and of the chemical changes involved in 

 their transformations is not radically different in the two types of 

 plants, the essential difference being in the preponderance of one 

 kind of activities, or chemical reactions, over another in bringing 

 about the metabolic processes which are characteristic of each 



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