14 
LABORATORY EXERCISES 
2. The instructor has scraped off and mounted some of the 
endosperm under the microscope. Examine it under both low and 
high power. What is the shape of the grains which you see? Are 
there markings on these grains? When a drop of iodine is placed 
at the edge of the cover glass, note the result. What, then, are 
these grains? Is any yellowish substance present? What is it? 
II. The Bean. Study some of the material which is scraped 
from the cotyledon of the bean seed and mounted under the micro¬ 
scope. Is much protein present here? When starch is as abundant 
as it is in the bean, why should the bean be looked upon as one of 
the protein foods? 
III. The Potato. Study a very thin shce of an Irish potato 
mounted under the microscope. Note the markings on the starch 
grains of the potato. Note that these grains are borne within cell 
walls. (See Waggoner, Page 35.) 
IV. How could you, under any circumstances, distinguish the 
starch which comes from corn, beans, or the Irish potato? In 
what parts of a plant may food be stored? What are the uses of 
the food which is so stored? 
V. Make drawings of the different types of starch grains which 
you have seen. 
VI. Arrange an exhibit of plants which illustrate various types 
of food storage. Attach to each a label bearing the name of the 
plant. Each member of the class may then determine in what way 
food is stored in each plant and may list in a tabulated form as 
follows: 
Name of plant 
Storage of Food 
In Stem 
In Root 
In Leaves 
Fruits 
