AMITOTIC DIVISION OF CELLS IN STEMS 



28l 



a microscope in the morning in a period in which rapid growth is 

 supposed to take place. Use the eye-piece micrometer and de- 

 termine the total length of a half dozen cells in a chain. Set the 

 preparation in bright sunlight and measure again at the end of two 

 hours. Find the increase in length and 

 determine amount for each cell. It will 

 be of interest to repeat the experiment, 

 placing the preparation in a dark room at 

 the same temperature for the same length 

 of time. It may be possible to find cells in 

 which division by amitosis, or mitosis is 

 in progress. This is much better seen in 

 staminal hairs of Tradescantia taken from 

 an unopened flower bud, and mounted in a 

 2 per-cent. sugar solution. Buds not more 

 than 5 mm. in length will furnish the best 

 material and the entire process will occupy 

 nearly two hours. 1 



359. Stages in the Mitotic Division of the 

 Nucleus. Prepare a number of sections of 

 the tips of roots of Podophyllum, Allium, 

 Zea, or Arisaema by the imbedding method, 

 staining to bring out the nuclear figures and 

 note the character of the nuclei in the cells 

 about to divide, and the various arrange- 

 ments of the chromosomes during the pro- 

 cess. 2 



360. Amitotic Division of Cells in Stems. 

 Cut a number of fresh sections of the 



Fig. 133. Stages in the growth of cells in the grow- 

 ing point of a seed-plant. A, cell newly formed by 

 division. B, cell in which active growth has begun. C, 

 cell which has attained nearly half its ultimate size. 

 k, nucleus, cy, cytoplasm, v, vacuoles. Somewhat 

 diagrammatic, X about 5°°- After Strasburger. 



1 Strasburger. Practical botany. 434. 1900. 

 •Strasburger. Practical botany. 434-458. igor 



