EFFECT OF MOISTURE AND TEMPERATURE. 35 



and the closed bottles was 82.08 and 85.02 percent, respectively. The 

 control sample oerniinated 85.45 per cent. That 37^^ C. is a])Oiit the 

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

 injury is shown l)y the followino- experiments. 



Preparations similar to those above mentioned were used, and after 

 beino- subjected to a temperature of 87^ 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 increasino- tlie tem- 

 perature, during an additional period of 6S days, from 37^ C. to a 

 maxinuun of 44'^ C, the injury was much more marked, especially in 

 the closed bottles. In the open ])ottles the vitality of the cabbage was 

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

 ity of 15.()(3 per cent. The onion seed fell from 1)5.7 per cent to 87 

 per cent when kept in an open bottle, and to 01 per cent when kept in 

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

 except that they became very dry; consecpiently 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 ])ottles was the 

 direct result of the higher humidity of the air immediately surrounding 

 the seed, and not because there was a deticiency 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 oidy 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 ])ecome 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. 0'^ 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 efi'ect 

 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. 



