8 BOTANICAL GAZETTE [JULY 
especially among the rosaceous seeds. Of these, the greatest 
activity occurred in apricot, 48 cc. of oxygen being liberated from 
hydrogen peroxide in five minutes by 0.13 gm. of imbibed seeds. 
The red Burbank plum had the lowest activity of any rosaceous 
seed, an equal weight of imbibed seeds liberating only 9.7 cc. of 
oxygen. In table II the catalase activity of hawthorn is given by 
periods from the fourth to the forty-second day, while the same 
70 
— 
iJ 
ers 
Bitlis as | | | | | | | ay 
3 190 5 20 22 30 oa 40 45 
Fic. 1.—Curves of catalase activity at 1, 3, 5, and ro minute intervals in a 
horizontal axes represent time in days after harvesting; vertical axes represent cc 
of O, liberated; temperature 25° C. 
data are presented graphically in fig. 1. There is an increase in 
catalase activity as after-ripening progresses. A determination 
made on the after-ripened seeds, 128 days at 10° C., suggests that 
this increase continues after the forty-second day, but at a very 
slow rate. This slowness of increase was observed by ECKERSON 
(t9) in her microchemical study of after-ripening in Crataegus. 
The stability of catalase activity in Amaranthus during the first 
month after harvesting is plain from table III. 
