FIGURE 21. Symmetrical binuclear conditions in cells of irradiated peas 



(from the work of Atabekova-'') . 



FIGURE 22. Asynmetrical binuclearity in cells of irradiated peas 

 (from the work of Atabekova-') . 



Adhesion and contraction of chromosomes and 

 disruption of their normal form lead to their 

 improper redistribution (Fig. 23). Along with 

 an increase in the number of chromosomes per 

 cell their diminution was frequently observed. 

 In general, the effect of this dose is character- 

 ized by endless numerical aberrations as well 

 as by the appearance of cells with two proto- 

 plasts. The effect of a dose of 36, 000 r was 

 lethal to the plant under field conditions. How- 

 ever, under laboratory conditions, a few seed- 

 lings were obtained whose roots were examined 

 cytologically. This examination revealed the 

 disintegration of chromosomes into the most 

 minute fragments, translocations, inversions, 

 deficiencies, and the formation of ring-shaped 



chromosomes. At anaphase, part of the chro- 

 mosome lags behind, others are ejected into 

 the cytoplasm, some are completely destroyed 

 and from their remains shapeless or spherical 

 bodies are formed. In individual cases, giant 

 cells with enormous nuclei were observed. 



The appearance of symmetrical binuclearity 

 and polyploidy was observed in plants obtained 

 from seeds and sprouts which had been irradi- 

 ated with stimulating X-ray doses. Among the 

 beneficial effects we must include the increase 

 in the number of divisions. Measurements of 

 the root diameters confirmed this assumption. 

 Stimulating doses of X rays induced intensified 

 cell division, which accounts for the increase 



83 



