Freezing Injury of Seed Corn 
25 
the cause of death. Chandler (1913), however, does not agree 
with this. He found no precipitation of proteids in the sap of 
young twigs of apple, plum, or pear and only slight traces of 
it in other plants. He calls attention to the fact, however, that 
frozen plant tissues, soon after thawing, take on a brown color 
and a soft watery condition, and that evaporation goes on much 
more rapidly from the surface of such tissues than it does from 
the surface of similar tissues which have not been frozen. 
PERSONAL INTERPRETATION 
One of the objects of the experiments reported in this 
bulletin was to determine the effect of freezing upon the cellular 
structure of the corn kernel and especially of the embryonic 
tissues, for the purpose of indicating the true cause of death 
resulting from freezing. It was thought that if death was due 
to some mechanical injury to the tissues or to disorganization of 
the cellular material, it would be indicated by a separation of 
the cells from each other, or by broken down cell walls, or by a 
difference in the appearance of the cell contents. lYith this idea 
in mind, careful studies were made both of frozen and unfrozen 
sections of embryonic material, permanently mounted and 
stained sections being used. Mechanical injuries of the cell 
structure or rupturing of the tissues were sought for with con- 
siderable care, as it was thought that these probably were the 
primary causes of the loss of vitality. 
Xo such injuries were found, however, in the embryonic 
tissues of the kernel. It was thought, then, that if such in- 
juries result at all from freezing, they should occur in the tender 
tips and stems of young corn seedlings. Sections of frozen 
tips and stems of such material were, therefore, studied. Even 
in this tender, rapidly growing material no rupturing or break- 
ing down of the cellular structure could be detected. However, 
from the observations of Wiegand (1906). Chandler (1913), and 
others, there can be no doubt but that a rupturing of plant 
tissues sometimes results from freezing; but from the evidence 
at hand, it must be concluded that death from freezing is not 
due to mechanical injuries but to some other cause. 
The protoplasmic and nuclear material of the cells of 
frozen and unfrozen tissues were studied microscopically; the 
same material being used for this as was used while searching 
for mechanical injuries. So far as was observed, no disorgani- 
zation or change of appearance was detected. It should be 
stated here, however, that observations of the cellular material 
were not very extensive, and the material used for study had 
