leaves, which completely changes the behavior 

 of hemp (Fig. 14). 



As has already been pointed out in the survey 

 of the literature, sex can also be changed by the 

 action of X rays. The same is to be expected in 

 hemp, which happens to be labile in relation to 

 sex. However, before turning our attention to 

 sex changes, we should examine the differential 

 survival of plants on the basis of sex (Table 22). 

 The total number of plants which reached the 

 flowering stage was 82 in the control and it 

 remained the same for the 1000 r dose, but, 

 beginning with 2000 r, the number of surviving 

 plants begins to fall steadily, so that with the 

 highest dosages we have only 11 to 13 plants 



surviving. If the effect of irradiation on male 

 and female plants is examined separately, it 

 will be noted that the slight initial predominance 

 of the female plants in the controls is supplanted 

 by a two -to -one predominance of female plants 

 over the male. This predominance of the female 

 plants leads one to believe that they are very 

 resistant to X rays. The first of the specific 

 changes of the male inflorescence are changes 

 in the bract and perianth. The imitation of 

 pistils is all the more complete in that their 

 ends acquire a reddish tinge. All the plants 

 (controls as well as irradiated plants) were 

 under identical germinating conditions, i.e. , 

 during 11 days they were subjected to shortened 

 days and only after that period did they receive 



FIGURE 14. Cessation of development of the top bud 

 and extreme deformation of leaves in hemp. 



51 



