KINETICS OF PRIMARY REACTIONS AND CHEMICAL PROTECTION .'} 1 9 



liigli oxygen ])ressures during irradiation. Protective action in the dip- 

 loid was nnicli weaker than in the haploid mIicii the yeast was irradiated 

 in water suspensions (Fig. 4). 



1. Hajjloid. 



2. Diploid. 



o 

 o 



0-2 



u 



.4-J 



I- 



o 



20 



0-6 1 



Oxygen tension (P atm) 



Fig. 4. 



1. Haploid. 



2. Diploid. 



_L 



0-2 0-6 



Oxygen tension (P atm) 

 Fig. 5. 



During irradiation of agar cultures the protective effect increases 

 in the diploid, reaching that of the haploid. Protective action in the 

 haploid, in agar cultures, is the same as in suspensions (Fig. 5). 



This can be explained as follows. The high resistance of the diploid 

 line, as compared to the hajiloid, shows that induced primary radiation 

 reactions developed more weakly in diploid cells and had a lower ionic 



