THE VIABILITY OF RADISH SEEDS (RAPHANUS SATIVUS L.) 
AS AFFECTED BY HIGH TEMPERATURES AND 
WATER CONTENT 
H. D. Waggoner 
The first important work on the effect of high temperatures upon 
the viability of seeds was done by Edwards and CoHn in 1834. From 
that date up to the present time considerable interest has been shown 
along this line and a large and valuable literature has accumulated. 
A large majority of the earlier workers in this field were interested in 
the maximum temperatures that seeds are able to withstand, and 
paid but little attention to the cause of the loss of vitality when seeds 
were heated at temperatures above their maximum. Recently several 
investigators have studied the effect of high temperatures upon proto- 
plasm, and important contributions have appeared that throw much 
light upon the real cause of death in seeds. 
It seemed advisable, owing to the lack of time, to confine the 
present paper to a detailed study of the effect of high temperatures 
upon the germinating power of seeds and to reserve the consideration 
of the direct effect of heat upon the living protoplasm of seeds for a 
subsequent study. 
A close study of the results obtained by earlier workers shows a 
wide difference in the maximum temperatures that the same or 
nearly related seeds can endure without injury. It further reveals 
the interesting fact that an intimate relation exists between the method 
employed in treating the seeds and the temperature at which serious 
injury or death occurs. Briefly, the methods heretofore employed 
are as follows : (i) The seeds were heated in water or in an atmosphere 
saturated with moisture. By this mode of treatment it is apparent 
that the seeds absorbed more or less water during the heating process. 
Authors using this method invariably report a low lethal temperature 
for the seeds used. (2) The seeds were heated in small closed con- 
tainers. By this method the seeds during the process of heating gave 
up moisture to a greater or less extent until an equilibrium between 
the imbibition energy of the seeds and the vapor tension of the inclosed 
air was established. The results obtained by this method varied 
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