389 
WHEAT. 
A detailed study of the relation of low temperatures to the growing 
of wheat has been made by 8S. G. Wright, of Indiana, from which I 
take the following conclusions: 
Sleet—When the winter wheat has its blades covered with ice that 
has fallen as sleet, and after the ice has melted off a microscopic exam- 
ination shows the cellular structure to be altered, the epidermis is 
separated from the underlying cells and there is a general disunion of 
the cells, and when the growing season comes the plants are found to 
be entirely dead. ; 
Sudden thawing—Wheat plants exposed to a very low freezing 
temperature in dry air if thawed out slowly are not much injured, 
but 1f thawed out rapidly the younger sprouts are completely killed 
and the older ones subsequently die. ,The similar rule obtains for the 
germination of seeds. When frozen seeds were quickly thawed out 
only 18 per cent germinated, but when slowly thawed out 86 per cent 
germinated. 
Freezing temperature of the juices of the wheat——The juice ex- 
tracted by pressure from the wheat has a lower freezing point than 
that of pure water when contained in its original living tissues, but 
after being extracted by pressure it freezes at an intermediate point 
below that of pure water. Again, the juice extracted from plants 
that have been exposed to a low winter temperature withstands freez- 
ing better than the juice from plants that have not had such exposure. 
For example, the juice within the cells was not frozen at —13° C., 
while that thrust out of the cells froze at —6° C.,,and in general the 
power to resist freezing 1s increased by exposing plants to the ordinary 
winter temperatures of the open air. 
Method of sowing—The best method of sowing wheat in order 
that 1t may withstand severe winter weather is (1) to avoid mulching 
or having any layer of porous material about the roots of the wheat, 
as experiment shows that this is a decided injury both to the winter- 
ing, the after growth, and the harvest. An average depth of seed 
planting of 1.5 inches is much better than three-fourths inch or 3 
inches. 
Range of temperature for germination.—According to Sachs, the 
minimum temperature is 5° C. and the maximum 37° or 388° C. 
According to Haberlandt, the temperature for germination ranges 
between 0° and —4.8° C. at the lower limit and 31° to 37° C. at the 
upper limit. Wright’s experiments, at a constant temperature of 
39° C., gave germination successful in forty-eight hours; at a tem- 
perature of 42.5° C. only a very few seeds could be made to germinate. 
At a temperature of 0° C. the seeds germinated in ten days; hence the 
extreme range of germinating temperatures for winter wheat of the 
varieties thus tested in Indiana is from 0° to 42.5° C. As to the effect 
