EFFECTS OF EXPOSING SEEDS 



109 



Summary 

 The exposure to radium rays of seeds previously soaked was fol- 

 lowed, in all instances by a retardation of growth. When seeds of 

 Lupinus a/dus were exposed for 17 hrs. to rays from radium bromide 

 of 1,500,000 X the seedlings produced by them grew only one half 

 as rapidly as normally. Exposure of soaked seeds of buckwheat for 



Fig. 9. Experiment 25. Roots and Root-Hairs of Seedlings from the Exposed Culture 

 {J^j, and from the Unexposed. Slightly Enlarged. Cf. figure S. 



24 hrs. to rays of the same strength retarded growth, and impaired 

 the general vigor of the plants. One experiment was tried with flax 

 seed, but an exposure of 48 hrs. (1,500,000 x) was followed by no 

 appreciable effect on the germination of the seeds. 



An initial retardation of the growth of white mustard after the 



