Freezing Injury of Seed Corn 
33 
occurs in corn containing different amounts of moisture. By 
freezing is meant here, the formation of ice crystals within the 
kernel. The observation was made by cutting thru the small 
end of the kernel, and by scraping the cut surface, or by 
digging in and around the embryo with a knife. The observa- 
tion was made immediately after removing the sample from the 
freezing chamber. 
The occurrence of ice crystals was not noted in all of the 
tests. In those tests where notes were taken all of the ears were 
examined. In the tables, the presence or absence of ice in all 
cases where examinations were made is indicated. It was very 
difficult to detect the ice in the samples of low moisture content 
because of the small amount present and because of rapid 
thawing. There is a possibility, therefore, that ice crystals may 
have been present in some of the samples and yet escaped detec- 
tion. The presence of ice is discussed in connectoin with the 
following investigations. 
COLOR OF EMBRYO 
Notes were also taken regarding the color of the embryo 
at the time when the germination tests were made. The color 
was designated as either dark or light. The light color repre- 
sents the natural color of a normal embryo. On the other 
hand, a dark or brownish color is quite characteristic of a 
frozen embryo. In a number of cases a part of the kernels on 
an ear would have a dark embryo and part of them a light 
embryo. Usually this condition was found to be associated with 
only a partial loss of vitality. 
For convenience of comparison, all ears which were sub- 
jected to a given range of temperature are grouped in the tables 
according to moisture content, a range of 5 per cent being 
allowed for each group. In all cases where there were more 
than one sample in a given moisture range an average for the 
group is given. 
RELATION BETWEEN MOISTURE CONTENT AND INJURY AT VARIOUS 
DEGREES OF FREEZING 
FREEZING AT TEMPERATURE RANGE OF 32° TO 28° F. 
The data for all the samples frozen at the temperature 
range of 32° to 28° F. are given in Table 5. It would seem 
from the data in this table that the vitality of corn with a high 
moisture content may be seriously injured or almost totally 
destroyed by such a light freezing a.s is represented bv the above 
temperature range when prolonged for a period of 24 hours. 
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