EFFECTS OF EXPOSING SEEDS 



131 



Experiment 30 



Object : To see if a variation in the time-interval between the 

 exposure of seeds to radium-rays and their germination, alters the 

 efficacy of the exposure to affect germination. 



November 19, 10 A. M. 



Three sets of six seeds each of Lit^imis albus, treated as follows, 

 were planted without soaking, in soil in flower pots. 



1 2 3 4 5 6 7 



Fig. 23. Lupinus albus. Duration of Exposure, 91-50 Hours. 



A. Exposed for 72 hrs. to RaBr2 1,500,000 x . Interval between 

 exposure and planting, 6 days. 



B. Exposed for 72 hrs. to RaBr, 1,500,000 x . Interval between 

 exposure and planting, 3 days. 



C. Exposed for 72 hrs. to RaBr, 1,500,000 x . Interval between 

 exposure and planting, o days. 



D. Control, not exposed. Planted at same time as A, B, and C. 

 Heights of the hypocotyls above the soil-surface as follows : 



