Oct. 21, I918 



Catalase and Oxidase Content of Seeds 



165 



as fresh seed; two-year-old amaranthus seed was about one-half as 

 active as fresh seed; and three-year-old Johnson grass seed was only 

 about one-third as active as one-year-old seed. 



OXIDASE ACTIVITY AS REI<ATED TO AFTBR-RIPENING AND CONDITION OP STORAGE OP 



SEED 



The oxidase activity of samples of Johnson grass seed a little over a 

 year old, which had been stored dry in cloth sacks at room temperature, 

 was compared with that of portions of the same original samples which 

 had been stored for a year between moist blotting papers at 20° C* 

 Comparative tests were made also with peach embryos which had been 

 stored for i month air-dry at room temperature and in moist blotting 

 paper at 7° C.;" and similarly at 25°. The peach seeds were taken from 

 the stony carpels before the period of storage, and the coats were removed 

 from the embryos just before grinding the latter for oxidase determi- 

 nations. 



Table XXIX gives the results of the experiments. One-year-old 

 Johnson grass seed which had been kept at a temperature slightly below 

 the minimum for germination, though otherwise under germination con- 

 ditions, showed considerably less oxidase activity than seeds from the 

 same original lot which had been stored dry. After grinding both lots 

 were dried in a desiccator before weighing. Peach embryos showed very 

 little oxidase activity under any conditions, and this activity did not 

 change significantly during incubation even at the after-ripening tempera- 

 ture, 7° C. 



TabIvE XXIX. — Oxidase activity as related to after-ripening and condition of storage of 



seed 



' Johnson grass seeds were kept in a condition of secondary dormancy by storing in moist blotters at 20°. 

 * Peach embryos stored thus after-ripen rapidly at 7°, but not at 2$°. 



78775—18 3 



