1914] ATWOOD—GERMINATION OF AVENA 395 
It will be noticed that the difference between the checks and 
the treated seeds becomes increasingly less conspicuous with the 
passage of time after harvest, that is, as after-ripening progresses. 
Tests were made of fresh seed hardly yet “out of the milk,” which 
tend to show that the seed is then neither lacking in vitality nor 
under the necessity of a long process of drying to secure “necessary 
protoplasmic alterations.’ One test (table IV) will show the 
tendency. 
TABLE IV 
- Pp t Additional Total 
No tested | Period |germination Then poeoiens bplonases 
5° 4 days 28 Seared 3 days..... hee 70 98 
5° OO 36 In 40 per cent O, 3 days.....| 34 70 
In this connection it is interesting to note that ZapE found that 
seed harvested unripe yielded a higher percentage of germination 
than seed harvested after ripening. It has been suggested (49) that 
seeds sometimes grow better just before ripening due to the presence 
of enzymes and protein-splitting products which decrease in amount 
with ripening as proteins are stored. However, if coat restrictions 
be concerned in the delay of after-ripening, it is possible that ripen- 
ing tends to increase the impermeability of this coat. It was also 
found that improved germination could be secured by complete 
results secured with A. fatwa may be illustrated by the instances 
given in table V. 
TABLE V 
s Check 
Time No. tested ago per cent 
eebhber tort 100 87 35 
Fiecember tors... 100 87 48 
4. Resprratory RaTI0.—In considering the effect of breaking 
the seed coat and its relationship to germination, the question arose 
as to whether if the seed coat acted as a restriction to oxygen entry, 
it might not be possible that after-ripening consists in a developing 
ability of the seed for anaerobic respiration. ‘This was found not 
