EFFECT OF MOISTURE AND TEMPERATURE. 35 



and the closed bottles was is^.us and sf>.<;^ percent, respectively. The 

 control sample germinated 85.45 per cent. That 37 C. is about the 

 maximum temperature at which air-dried seeds can be stored without 

 injury is shown by the following experiments. 



Preparations similar to those above mentioned were used, and after 

 being subjected to a temperature of 37 C. for 219 days, there was no 

 appreciable loss in vitality, except the deterioration of 4 per cent in 

 the case of the cabbage seed that was kept in an open bottle, and 6.3 

 per cent in the seed from a closed bottle/' But by increasing the tem- 

 perature, during an additional period of 68 days, from 37 C. to a 

 maximum of 14 C., the injury was much more marked, especially in 

 the closed bottles. In the open bottles the vitality of the cabbage was 

 lowered from 91.3 per cent to 77 per cent, representing a loss in vital- 

 ity of 15.66 per cent. The onion seed fell from 95.7 per cent to 87 

 per cent when kept in an open bottle, and to 61 per cent w T hen kept in 

 a closed bottle. The beans showed no apparent injury in either case, 

 except that they became very dry; consequently there was a retarda- 

 tion in germination as a result of the slow absorption of water. 



The greater loss in vitality of the seeds kept in the bottles was the 

 direct result of the higher humidity of the air immediately surrounding 

 the seed, and not because there was a deficiency in the supply of fresh 

 air, as might be readily assumed. In the open receptacles the additional 

 amount of free water expelled, as a result of the increase in tempera- 

 ture, was allowed to escape, while in the sealed bottles it only gave 

 rise to a relatively moist atmosphere, and consequently to a premature 

 death of some of the seeds. If seeds are to be so confined, they should 

 be previously dried at a temperature at which they are to be stored. 



All of these seeds had become very dry and brittle. The odor of 

 the air confined within the sealed bottles had become very unpleasant; 

 likewise there was a marked change in the color of the seed coats of 

 the inclosed seeds. 



SUMMARY. 



Most seeds if kept dry are not injured by prolonged exposures to 

 temperatures below 37 C. (98.6 F.), it being immaterial whether they 

 are in open or in sealed bottles. 



If the temperature be increased above 37 C., vitality is seriously 

 reduced. 



If seeds are kept in a moist atmosphere, a temperature even as high 

 as 30 C. (86 F.) works much injury in a comparatively short period. 

 The degree of injury rapidly increases as the temperature rises. 



Provided the degree of saturation is the same, the deleterious effect 

 of moisture is fully as great in open as in closed bottles. 



Only cabbage, onion, and beans were used for this experiment, the carrot and 

 the lettuce seed being omitted. 



