» 
1914] ATWOOD—GERMINATION OF AVENA 405 
reason it is of interest to note that the temporary ‘‘ wound effects” 
noted for other tissues with carbon dioxide as a basis of decision, 
do not hold for the oxygen intake of Avena fatua. 
As the early germinative delays of A. sativa are so much less pro- 
nounced than is the case for A. fatua, it is of interest to compare 
the oxygen-absorption 30 
rates for the two 
(fig. 10). The tame eas. SERA 
oat shows a_ higher ee eee isi 
rate throughout. It 
was impossible ance: comreamaay ceeigc = Cay Same & 
to carry out these ra 
tests (summarized in -227———7__—sd Pos 
fig. 10) until April, pf 
when the comparative vy 
difference in germina- emma CERES, 
tive delay between a ~ a — 
the tame and the wild rere Bea Gags eeet 
eat is much léss than 4g) te 1 Sees SATEREL 
in the preceding oat 
autumn. This makes sapemeoane ea 
it seem probable that a a 
when fresh seed may : 
again be obtainable, eR iets HE ReeGeD ERE 
the differences in rate ees 
found above, though -06 190 Hours 30 50 
quite marked, may Fic. 11.—Rates of oxygen absorption for 
be even more con- intact wild oats before and subsequent to after- 
spicuous. sipening, to tern Oh Oe Pe a 
weight; rates in winter, solid line; in spring, 
In figs. 11-13 are heoken: tne 
shown respectivel pace 
the effect of nee on the rate of oxygen intake by intact 
seeds, seared seeds, and seeds run in an atmosphere of ee 4 
per cent oxygen. The temperatures employed were identical 65 
the 24 tests here summarized. In each case the winter rate 1s 
indicated by the unbroken lines, and the spring rate by broken 
lines. A consistent increase in the rate of oxygen absorption in 
