EXERCISE No. 4 

 A STUDY OF THE CORN KERNEL 



Object: To become familiar with the different parts of 

 the kernel of corn. 



Material : Good and poor kernels of corn for comparison, 

 and a hand lens. The corn should be soaked in warm water 

 for an hour before being used for this exercise. 



Method : Draw an outline of the kernel as it lies on the 

 desk, germ side up. The drawing should be made 3| inches 

 long. Carefully remove the tip cap of the kernel with a 

 knife. Locate the tip cap in the drawing, and label it. 



(a) Carefully remove the hull with a knife, in one piece if 

 possible. Label the hull in the drawing. 



(b) Scrape off the mealy layer (aleurone) which con- 

 stitutes the second covering of the kernel. It is usually much 

 thicker than the hull. Make a shady line next to the hull 

 for the aleurone layer, and label it. 



(c) Carefully remove the germ (embryo), which is found 

 in the center of the front of the kernel and toward the tip. 

 It extends from \ to f of the length of the kernel. The germ 

 is rich in fat and oil. The embryo stem points toward the 

 crown and the embryo root points toward the tip of the 

 kernel. Both of these are parts of the embryo. Show this 

 in the drawing. 



(d) Break the remainder of the kernel (the endosperm) 

 into two parts, lengthwise. Scrape the white starchy 

 portion off the horny starch portion. The white starchy 

 portion occupies the crown end of the kernel above the germ 

 and it also surrounds the germ toward the tip. See if you 



18 



