1921] PACK—JUNIPERUS 53 
was probably due to increased acidulation in the presence of an 
abundance of CO, and H,O which could favor the digestion of fats 
and germination (25) _/Desiccation and moistening again of seéds 
at about the forty-fifth day after being placed in the germinator 
/shortens the after-ripening period from 5 to ro days. This may 
/ be-due to one of the following causes: (1) earlier after-ripening of the 
| coats, as they are found to split off more readily when desiccated, 
(2) upsetting of the chemical equilibrium by the great extraction 
| of water, or (3) the increase of H* ion concentrations. 
Discussion 
CaTALASE.—The catalase activity, as has been noted by previous 
investigators (1, 6), was found to bear some relation to respiration. 
Increased catalase activity accompanied the intense respiration of 
Juniperus seeds stored in high percentages of oxygen, as decreased 
TABLE XIX : 
INCREASED CATALASE ACTIVITY WITH DEVELOPMENT (FIGURED PER UNIT DRY WEIGHT) 
OXYGEN IN CC. LIBERATED DURING 
CONDITION OF SEEDS 
. I min. 5 min. | ro min. 
sey clkin® See wee SA A RECT ge a 2.5 5.4 5.8 
Alter, 45 days 5. eats Seas En 3.6 7-5 9.1 
BIO Oh cavest eu. - ak 5.0 Q.1I | 12.0 
After 100 days a t 5° C. (coats split)...... +4 12.2 14.4 
After 130 days a gC, (oedema): yc. ss 10.5 23.1 28.5 
catalase activity accompanied the low respiration of seeds stored 
in low. percentages of oxgyen. With the intense respiration at 
high temperatures there was an increased catalase activity, even 
though the seeds did not after-ripen or germinate. The highest 
catalase activity and the most intense respiration per unit of dry 
weight was found in the seedling stage (cf. tables XIX and XVII). 
The desiccation of seeds to a slight extent, which makes for a 
rapid absorption of oxygen through the coat, increased the catalase 
activity. Desiccation to the extent of retarding respiration reduced 
the catalase activity. Table XX shows these results. Both the 
respiration and the catalase activity of seeds were reduced at will 
