96 
Journal of Agricultural Research 
Vol. XXII], No. * 
possible upon seedling vigor, upon the development of the resulting 
plant, and upon crop yield. The work of Kidd and West (26) in bringing 
together under the head of “Physiological predetermination” the result 
of previous work bearing on the latter subject, as well as the work 
referred to on previous pages, emphasizes the probability that the periods 
of maturation and germination of the seed, and perhaps also the inter¬ 
vening period of after-ripening, may be about the most impressionable 
stages in the life history of the plant for the reception of influences 
which are capable of modifying fundamentally the whole future course 
of its development. In future investigations along this line possible 
varietal differences should always be kept in mind. 
SUMMARY 
(1) Newly harvested cereals frequently do not germinate well at 20° C. 
or above* under the ordinary conditions for germination tests. This fact 
has caused difficulty in administering State seed laws in the winter- 
wheat areas where harvesting precedes sowing by only a few weeks and 
the current crop is used for seeding. 
(2) The embryos of the cereals investigated are never essentially 
dormant, dormancy being imposed by coat structures. 
(3) Artificial dry heating, opening the coat structures over the embryo 
with incidental wounding of the scutella, and cutting off the distal ends, 
were effective in varying degree in inducing the germination of not after- 
ripened or partially after-ripened wheat, oats, and baidey at room tem¬ 
perature. 
(4) Removal or weakening of the coat structures over the embryos of 
wdieat by the use of sulphuric acid was exceedingly effective in inducing 
complete germination in a minimum length of time. 
(5) Artificial drying, to be completely effective, must be continued 
for a week or more and thus unduly delays the germination tests. 
(6) Removal of the scales from oats and barley increased their germina¬ 
tion somewhat, and removing the loose pericarp and tegumentary struc¬ 
tures over dormant barley embryos caused complete germination at 
room temperature. 
(7) Increased oxygen pressure in the atmosphere greatly increased the 
germination at room temperature of partially after-ripened wheat. 
(8) The mechanical treatments, wounding and corrosion with sulphuric 
acid are very tedious processes and entail great danger of subsequent 
decay. 
(9) Presoaking for even one hour in excess of water accelerated the 
germination of partially after-ripened wheat, oats, and barley but 
decreased the total germination. The soaking increased the rate of 
imbibition, and apparently the injurious effect upon total germination 
was the result of limiting gaseous exchanges by saturation of the surface 
layers of the grain with unaerated water. Presoaking half an hour in 
running aerated water did not seem to have any ill effect. 
(10) For the germination of not after-ripened cereals, the seed bed 
should be such as to supply abundant water available for rapid absorption 
by the grain, but to do this without flooding the grain. Somewhat 
supersaturated absorbent cotton in Petri dishes satisfies these require¬ 
ments if the grain is placed lightly on top of the cotton. Barely saturated 
blotters give equally good results if the grain is placed between the 
blotters, but not if the grain is placed on top of the blotters. 
