REST PERIOD STUDIES WITH SEEDS 45 



Seeds soaked six hours and then frozen, were badly damaged by 

 such treatment, but etherizing, especially for the 12-hour period, 

 seemed to have the power of causing a greatly increased percentage of 

 germination. 



A summary of all of the treatments in each table shows that the 

 average percentage of germination for all check seeds was 47.8; for 

 all plantings after 12-hour ether treatment, was 56.3 ; and for all the 

 24-hour etherization treatments, 52.6 per cent. Comparing the checks 

 with the ether treatments it is seen that former germinated in twenty- 

 nine cases on the first day on which germination was recorded for that 

 series; the 12-hour ether exposure in forty-seven cases; and the 24- 

 hour ether treatments in only thirty cases. The 12-hour treatment, 

 when compared with the check, shows a hastening of germination in 

 thirty-six cases, and a retardation in only eighteen instances, while 

 the 24-hour exposure hastened the germination in twenty-five instances, 

 and retarded it in twenty-four. 



SUMMARY AND CONCLUSIONS 



Seed studies carried on at the Missouri Agricultural Experiment 

 Station were begun in 1907 and continued for seven years. Primarily 

 these studies were conducted for the purpose of investigating the rest 

 period. 



Preliminary tests in 1907 and 1908 showed, first, that seeds of 

 many annual plants are able to germinate while quite immature; and, 

 second, that seeds of more than half of the species grown in Missouri 

 have a pronounced rest period. Also that of the species having a rest 

 period, by far the greater percentage are woody forms. 



The chief purpose of the seed investigations carried on during 

 the years 1911, 1912, and 1913, was to confirm the existence of a 

 rest period in seeds, and to find to what extent the species are in- 

 fluenced by this phenomenon. 



Other objects sought thru these later investigations were: If 

 seeds have a rest period, when does the resting phase set in and can 

 it be broken by treatments ; what agents are most effective for break- 

 ing the rest ; to what extent do seeds respond to treatments in general 

 while dry and while moist ; effects of treatments on germination aside 

 from hastening or hindering the growth ; and, a comparison of all of 

 the foregoing with regard to the different species and orders. 



Special efforts were put forth to secure as many different kinds of 

 seeds as possible. Altogether, during the two seasons of 1912 and 

 1913, nearly 200 species, representing fifty-one orders, were collected. 

 Each planting usually consisted of 100 seeds and there were more 



