28 FIELD AND LABORATOKY STUDIES OF CKOPS 



Remove the outer covering from some of the soaked 

 grains and observe the location of the color. Where is the 

 white color located in the white grains? What is the color 

 of the hull of the yellow grain? The color of the endosperm? 

 . What is the color of the red grains after the hull has been 

 removed? 



Discussion: The corn kernel is composed of four dis- 

 tinct parts: (1) the hull, which i^ the thin, outer layer which 

 covers the entire grain, (2) the aleurone layer, which is very 

 thin and located just under the hull, (3) the endosperm, which 

 occupies about three-fourths of the entire grain and (4) the 

 embryo, or germ, which is the Hving part of the grain. 



The endosperm is composed very largely of starch, and 

 furnishes the food , for the young plant after germination 

 and until it has gotten its roots into contact with the soil 

 and its leaves exposed to the air. The endosperm is 

 made up of two kinds of material, one white and starchy 

 and the other hard and horny. The embryo is embedded 

 in the endosperm just under the groove which occupies 

 one side of the grain. The little plant which is snugly 

 folded into the cavity can be seen with the naked eye after 

 the surface of the grain is cut away with a sharp knife. 

 When the grain is planted in the soil, it absorbs moisture 

 ^nd, if temperature conditions are favorable, the little plant 

 pushes its roots out into the soil, and extends its leaves up 

 into the air. 



