1909.] Latent Life of Resting Seeds. 431 



Temperature Extremes. High Temperatures. 



I\ 11111 Ul IjccU. 



Tempera- 

 ture. 



lime 



seeds 

 exposed. 



.Percentage 

 germina- 

 tion. 



Reduction 

 with Fehlmg s 

 uesu. 



Biuret 

 reaction. 



| 



| Tryptophane 

 reaction. 





° C. 



hours. 











Wheat* 



99—100 



2 



48 



Strong 

 » 



Faint 



Good. 





99 — 100 





32 





!J 





99 — 100 



1 



48 





» 



)> 



Wheat 



99 — 100 



1 



24 



>< 





!> 





99 — 100 



4i 







)» 





» 



Barley 



99 — 100 



4£ 



6 



» 



» 



» 



Oats 



99 — 100 



4$ 



24 







J! 



Barley 



99—100 



6i 







>• 



!! 



1. 





99 — 100 



6i 







» 



!> 



>• 





99—100 



6i 







•I 



» 



» 



Wheat 



99 — 100 



16 







)* 



>! 



» 





99—100 



16 









1. 







99 — 100 



16 







)) 



» 



» 





122 



1 







>> 



Very faint 

 )> 



Fairly good. 



Rye 



122 



1 







Faint 



Grood. 



Maize 



122 



1 







Faintest trace 





Very faint. 



Wheat 



124 



1 







Strong 



None 



Fairly good. 



Eve 



124 



1 



o 



Faintest trace 





Faintest trace. 





124 



1 







None 



)j 



None. 



Oats 



126 



1 







Faintest trace 







Wheat 



127 



1 







Faint 





Faint. 



Oats -.. 



127 



1 







None 





None. 



Wheat 



128 



1 







Faintest trace 





Faintest trace. 





130 



1 







None 





None. 



Barley 



130 



1 







Faintest trace 









130 



1 







None 







Barley 



130 



1 







j> 







* [In my paper on the vitality of seeds, wheat and barley are given as withstanding a day's 

 dry heat at 100° C. The error is due to the transcription of 1 h. into 1 d., and the records are for 

 one hour's heating and not one day's, the somewhat higher percentages being possibly due to more 

 perfect drying. — Alfred J. Ewart.] 



naturally vary somewhat, since their structure, composition, and power of 

 retaining moisture all vary to a certain extent. 



The diastase and the erepsin of the resting seeds appear to be almost 

 equally resistant to dry heat, or at least there is more variation between the 

 diastases of different resting seeds than between the diastase and erepsin of 

 the same seed. 



Above 100° C. no seeds of any kind were found to be capable of germina- 

 tion, and the germinating power was absolutely lost in those seeds which had 

 been subjected in a dry condition to a temperature of 99° to 100° C. for 

 5£ hours. Just* showed that as seeds are dried their resistance to dry heat 

 increases, and von Hohnelf found that many fully dried seeds could with- 

 stand an hour's exposure at 110° C. 



* ' (John's Beitrage,' vol. 2, 1877. 



t ' Haberlandt's Wiss.-prakt. Unters.,' vol. 2, 1877. 



