BIOLOGY OF HIGHER SEED PLANTS 35 



the elongating zone in the bud derived from a meri- 

 stem, as in roots ? Be able to explain the similari- 

 ties and differences between roots and sterns in these 

 respects. 



c. Summarize in your notes the similarities and differ- 

 ences between root growth and stem growth by 

 means of buds. Distinguish between the growth of 

 woody and herbaceous stems. Consult the text sum- 

 mary (pp. 69-72) on the growth of roots and stems. 



C. THE CELL AND CELL DIVISION 



1. Minute structure of the cell. 



a. Select a well-stained cell in the cortical region just 



above the meristem and study it carefully with the 

 highest-power ocular and objective available. Read 

 the text description of such a cell. 



b. Do you see any indication of the mesh structure of 



cytoplasm mentioned in the text ? What is the 

 structure of the chromatin ? Can you find the 

 nuclear vacuole surrounding the nucleolus ? 



c. Draw the cell you are observing, greatly magnified, to 



show the structure of the cytoplasm and the nucleo- 

 plasm (chromatin) as they appear in your section. 



d. Observe the chromatin in other nuclei of the root tip. 



Do you see any of the variations in its structure 

 noted in the text ? 



2. Cell division (mitosis). 



a. Prophase. Select a nucleus in a root-tip cell which 

 shows the condensed condition of chromatin in the 

 form of chromosomes. 



(1) Chromosomes. Is the nuclear membrane still pres- 

 ent in a nucleus with chromosomes? What is 



