228 



A. M. KUZIN 



10 50 100 500 1,000 5,000 10,000 25,000 



Rad 



jrig_ 3. — Percentage mitoses in Vicia faba roots immersed (for 24 lir) in water extracts 



from irradiated and normal leaves. 



carried out with 8 different plants gave similar results. Figure 4 gives 

 the data from this series of experiments. 



What metabolic changes take place in irradiated leaves which lead 



M-2 



63-4 



no 



T-rrr 

 368 



^ 



Sunflower Haricot Melon Pumpkin 



Beans Radisii Cucumber Maize 



Control - Beans on water 



I I Normal (beans on extracts from unirradiated leaves) 



V///^^cA Experiment (beans on extract"; from irradiated leaves) 



Fig. 4. — Mitoses in the roots of Vicia faba treated for 24 hr with extracts from irradiated 

 (25 kr) and unirradiated leaves of different plants. 



to the increase in antimitotic substances. Kopilov's investigations 

 showed that extracts of irradiated leaves were far more quickly oxidized 

 by atmospheric oxygen than extracts of normal leaves. The results of a 

 series of experiments are given in Fig. 5. The intensity of oxygen 

 absorption by homogenates of freshly rubbed tissues of irradiated and 



