88 Agricultural Chemistry. 



of growth, the leaves, stems and roots are contributing their re- 

 serves for the production of seed. Migration of food constituents, 

 especially of starch, nitrogen compounds and ash constituents, 

 from the root or leaves now assumes prominence. While the ash 

 constituents accumulate in the seed only in small amounts, 

 sufficient for the growth of a vigorous seedling, some of the 

 organic reserve compounds may be stored in excess, giving dis- 

 tinctive character to the seed. This is true of starch, which gives 

 the cereal grains peculiar value for the manufacture of foodstuffs 

 and of alcoholic products. It is also true of fats and proteins, 

 which give to cotton and flaxseed high commercial values as 

 sources of oils and as protein-furnishing constituents of rations 

 for live stock. Starch and fat serve the young seedling as 

 sources of energy for growth and as material for carbohydrate 

 construction until it becomes independent of the seed; the pro- 

 teins of the seed furnish simple nitrogenous structures from 

 which the proteins of the seedling are formed. 



Compounds of the plant. As a result of the activity of the 

 various plant organs, there is produced a great variety of com- 

 pounds, partly transitory in nature and partly of permanent 

 character. The following classification is a brief plan of division 

 for the compounds of the plant : 



("Carbohydrates 

 Water ^ Non- I Fats and waxes 



I Nitrogenous i Terpenes and essential oils 



Dry Matter 



1i> iirogeiiouM i ierpenes aim 

 I Organic acids 

 f Proteins 

 XT:X J Amino-acids 



VNitrogenoasj -des 



lAmines and alkaloids 

 Ash containing ( Salts of organic acids 

 compounds ( Inorganic compounds 



Water holds a place in the chemistry of the plant the import- 

 ance of which can hardly be realized. Besides its physical func- 

 tions of transporting food materials and regulating the tempera- 

 ture of the plant, it is responsible for maintaining the turgidity 

 of the individual cells, thus giving form and rigidity to immature 



