Freezing Injury of Seed Ccrn 
13 
respectively thru (1) the plumule, (2) the medial area between 
the plumule and root, and (3) the primary root. The embryo 
is seen to be a miniature plant, with its vegetative organs fairly 
distinct. 
FREEZING INJURY NOT DUE TO ARRESTED DEVELOPMENT 
OF THE EMBRYO 
The loss of vitality or lack of germinative power occasioned 
by autumn freezing is not due merely to arrested development 
of the seed. There is much experimental evidence as well as 
general observation that corn acquires the power of germina- 
tion very early in the development of the kernels. Corn 
Table 1 — Viability of corn harvested at various stages of 
ma turity (1915 - 1 91 7 ) 
Date of selection 1 
Weight of 100 kernels 
Germination 
1915 
1916 
1917 
1915 
1916 
1917 
1915 
1916 
1917 
Grams 
Grams 
Grams 
Per cent 
Per cent 
Per cent 
Aug. 22 
Aug. 22 
Aug. 2 C 
11.2 
15.4 
10.0 
66 
83 
92 
Aug. 29 
Aug. 29 
Sept. 4 
16.0 
19.7 
15.4 
88 
94 
94 
Sept. 5 
Sept. 5 
Sept. 11 
18.9 
22.3 
20.0 
89 
94 
99 
Sept. 12 
Sept. 12 
Sept. 18 
23.0 
25.9 
23.8 
95 
96 
99 
Sept. 19 
Sept. 19 
Sept. 25 
27.0 
28.2 
28.6 
96 
96 
99 
Sept. 26 
Sept. 26 
Oct. 2 
29.9 
31.4 
30.9 
94 
96 
99 
Oct. 3 
Oct. 3 
Oct. 9 
31.0 
32.3 
31.0 
96 
97 
100 
1 Corn was in the milk stage at the first selection each year. 
Date 
of 
selection 
Three year average 
Condition of grain 
Days 
since fertil- 
ization 3 
Weight of 
100 kernels 
Ratio wt. 
of embryo 
to wt. of 
kernel 2 
Germina- 
tion 
Aug. 24 
Milk stage 
20 
(: Grcms ) 
12.2 
.078 
{Per cent) 
80 
Aug. 31 
Late milk stage 
27 
17.0 
.105 
92 
Sept. 7 
Roasting ear 
34 
20.4 
.110 
94 
Sept. 14 
Late roasting ear . . . 
41 
24.2 
.103 
97 
Sept. 21 
Denting 
48 
27.9 
.106 
97 
Sept. 28 
Glazing 
55 
30.7 
.112 
96 
Oct. 5 
Mature 
62 
31.4 
98 
2 Data for 1917 only. 
^Pollination occurred on August 1. July 31, and August 10, in 1915, 1916, 
and 1917 respectively. 
