CHAPTER 



I OCorrelations between 

 Protein-Carbohydrate 

 Metabolism and Mineral 

 Deficiencies in Plants 



ROBERT A. STEINBERG 



I 



interpretation of the data on protein and carbohydrate 

 metabolism of the green plants subjected to mineral deficiency has been 

 complicated by the use of a wide range of climatic conditions, differ- 

 ences in sampling, and the nonspecific nature of the methods of chemi- 

 cal analysis. Practically no information exists concerning the chemical 

 mechanisms of symptom formation with mineral deficiency. The great- 

 est difficulty, however, can be attributed to our meager information on 

 the organic nutrition of the plant. It is for this reason that a brief 

 introduction dealing with protein and carbohydrate metabolism is 

 advisable before attempting to evaluate the effects of mineral deficiency. 



PROTEIN AND CARBOHYDRATE METABOLISM 



A diagrammatic outline of the probable course of organic nutrition 

 has been published by Gregory and Sen (14) and is here reproduced 

 in Figure 1. Chibnall (6) has pointed out how adequately it represents 

 the facts as far as they are known. 



An examination of the chemical reactions indicated in this diagram 

 reveals that a breakdown of hexose molecules is assumed to precede the 

 formation of organic acids. Interaction of these with ammonium ion 

 results in production of amino acids. Protein is formed through con- 

 densation of amino acids and these are regenerated on subsequent 

 hydrolysis. Amides may or may not participate in protein formation. 

 Respiration, i.e., oxidation with liberation of carbon dioxide, is repre- 



