28 PLANT BIOLOGY 



closed by lines more or less dark in color called 

 cell-walls. (These parts are usually seen more clearly 

 if the light is largely excluded by closing the dia- 

 phragm in the stage.) 



a. Describe the general appearance of the membrane, 



stating of what it is composed. 



b. State whether or not the cells in the various parts of 



the membrane differ in size and shape. 



2. The cell-wall incloses a semifluid substance which makes 



up the cell-body. Describe the appearance of the 

 cell-body. 



3. Within the cell-body, often near the center of the cell, 



is usually a tiny object called the nucleus. Describe 

 the location, shape, and color of the nucleus. 



4. Make a drawing of three or four adjacent cells, several 



times as large as they appear under the microscope. 

 Label cell-wall, cell-body, cell-nucleus. 



5. (Demonstration.) Secure some growing sprays of Elodea 



(a common water plant) . Pull off one of the youngest 

 leaves near the tip end, put it on a 

 slide with a drop of water, and cover 

 with a cover glass. Let the prepara- 

 tion stand in a warm place for a time. 



Examine with the high power the cells of 

 which this leaf is composed. 



Within each cell note some green bodies 

 called chlorophyll bodies (from Greek, 

 meaning leaf green). These are the 

 bodies which aid in starch manufac- 

 ture in green leaves. (See 31.) 



a ' Describe tne form > color > and use of 

 chlorophyll bodies. 



b. Carefully watch the chlorophyll bodies in several 



cells and describe any movements you see. These 

 movements show that the substance of the cell is 

 in motion, and is carrying the chlorophyll bodies 

 along with it. 



c. Make a drawing at least 2 inches long of one of the 



cells with its chlorophyll bodies. Label cell-wall, 



