STUDIES IN POLLEN, WITH SPECIAL REFERENCE TO LONGEVITY 
775 
ealcium chloride in the bottom. The receptacles were then placed in 
constant-temperature ovens, at the temperatures noted in tables 18, 19, 
and 20. At the end of each specified interval, an envelope was withdrawn 
from each jar, dnd with its contents field pollinations were made. 
After 
a suitable interval, the ears were examined to determine whether fertili- 
zation had occurred. Ability to fertilize was the only test of viability 
used, since uniform results could not be obtained in artificial germination 
experiments. 
In table 18, fertilization is indicated by a plus sign, and lack of fertili- 
zation by a minus sign. The number of ears pollinated was either one, 
two, or three, as indicated by the number preceding the sign. 
TABLE 18. Corn PoLuEN StorED AT DIFFERENT TEMPERATURES OVER 
Catcrium CHLORIDE. 
Length of storage 
| 
| 
1915 
Fertilization when stored at 
0° C. 
D100 60 00.6 
These results point to the fact that moderately low temperatures are 
most favorable for storing corn pollen, provided the humidity is low. 
It 
should be noted that pollen stored at a temperature of —17° C. was not 
capable of effecting fertilization. In this series, no pollinations were made 
