200 



EFFECTS ON PLANT RESPIRATION 



rays of radium, twenty wheat grains, weighing (dry weight) .50 gm., 

 were placed before soaking, in contact with the walls of a sealed 

 glass tube containing 10 mg. of RaBr2, of 1,500,000 activity. The 

 duration of exposure was 54 hours. 



0.5 _ 



0.4 



tyj 







0^ 



0.2 



0.1 



0.0 



3.30 5:30 P. M. 



Time 



Fig. 51. 



^M. 9:30 11:30 i;30 3:30 5;30 



These seeds, together with 20 others, also weighing .50 gm., and 

 serving as a control, were soaked in water over night, and arranged 

 in the respirometer, as described in Experiment 77. 



ccc 



30 



o 1 



26° 



22° 







Experiment 79. 

 Effect of radium rays o;t respiration 

 of germinating wheat. First 8 hrs. 



9:30 10:30 11:30 12\10 



1:30 

 Time 



Fig. 52. 



.oo. 



2:30 



3:30 



4-30 



5:30 



