Igt1]} GOODSPEED—TEMPERATURE COEFFICIENT 223 
The criterion of complete development was the appearance 
of the green shoot above the plumule sheath or the formation of . 
roots from the swollen radical extremity. The normal stages 
observed in the germination of barley are, first, the protrusion of 
the calyptrogen and a rapid development of the three primary 
roots therefrom, and second, the appearance, at a shortly later 
period, of the plumule sheath, within which the leaves of the plu- 
«mule are contained. The effect of all temperatures above 64°C. 
for the time intervals mentioned below was to inhibit in every 
case the normal development of the radicle. Development appeared 
in the plumule after intervals varying from 15 to 30 hours, and con- 
tinued slowly until at the end of two days the green shoot began to 
show. From 2 to 3 days later adventitious roots began to take form 
from the basal portion of the plumule sheath, probably from the 
point of origin of the procambium strands that enter the scutellum, 
leaves, and radicle. The germination and subsequent development 
of certain seeds subjected to a temperature of 66° C. for 5 minutes 
was observed through a period of five weeks, and it was noted 
that after the appearance of the adventitious roots growth pro- 
ceeded rapidly, and at the end of this period these plants com- 
pared favorably with those germinating normally and growing 
for an equal length of time. 
Temperature Centigrade Duration of life coefficient for us Cc; 
70 13-2 
69 a 23 L I ¢ 
68 2o55 11 
67 4- 5 - - Jove 
66 5- 6 1.3 
65 6-8 { i4 
64 Y peg Ea 
63 10-12 to 
62 tik? 
.. 
61 15-16 . je 
60 18-19 a 
59 21-24 [ 1.1 
58 24-26 J 1.3 
57 32-35 } 1.3 
56 42-47 ) 15 
55 65-70 
Average temp. coefli- 
ent 1.27 
