Freezing Injury of Seed Corn 
IT 
Table 3 — Relative moisture content of embryo and endosperm 
Description of grain 
Moisture content 
Embryo 
Endosperm 
Ratio embryo 
to endosperm 
OLD CORN 
Per cent 
Per cent 
Air-dry 
7.91 
7.6 
1.03 
Embedded 24 hours in moist soil . . . 
21.37 
15.62 
1.36 
Embedded 48 hours in moist soil . . . 
36.81 
20.83 
1.77 
NEW CORN 
Selected from field before dry 
31.1 
24.1 
1.29 
Same corn when practically air- dry . . 
10.5 
12.9 
0.81 
New Corn. Twenty-five seed ears were selected in the fall 
before becoming* well dried out. Twenty kernels were removed 
from each ear and the relative moisture content of the embryo 
and endosperm determined, giving a ratio of 1.29. When this 
corn had become practically air-dry, the ratio of the moisture 
content of the embrvo to that of the endosperm was reduced 
to 0.81. 
PHYSICAL EFFECTS OF FREEZING 
ICE FORMATION IN KERNELS 
It is known that ice is formed in kernels of immature corn 
when exposed sufficiently to freezing* temperatures, and that 
death frequently follows such exposure. The temperature at 
which ice is formed within the corn kernel depends very largely 
upon the moisture content of the kernel. For the most imma- 
ture seed tested in these experiments, containing* 60 to 80 per 
cent moisture, the freezing point was only slightly below the 
freezing point of water. On the other hand, no ice formation 
could be detected in air-dry kernels or in kernels containing 
less than 18 per cent of moisture, when subjected to the lowest 
temperature observed : namely 10° F. below zero. 
During the freezing process, in case the moisture content 
was excessive, the water seemed to be drawn from the cells into 
the larger spaces around the embryo, and about the plumule, 
the primary root, and the root sheath, and doubtless into the 
smaller spaces between the cells. In these larger spaces, which 
may be seen in Figures 1. 2, 5, 6, T, and 8, the ice would form 
in a solid sheet around the tissues. In fact, when very moist 
kernels were exposed to the lower temperatures, the whole kernel 
