54 BOTANICAL GAZETTE [JANUARY 
by submerging them in water. Although increased catalase 
activity generally accompanied intense respiration, this relation- 
ship did not always hold, for when seeds were submerged a long 
time the catalase activity slowly increased, but there was no increase 
of respiration intensity. An examination of tables IX and XVII 
will show that the catalase gain was proportionally very much 
larger than the respiration gain during after-ripening. It will also 
be noted that the catalase gain was greatest at 5° C., where the 
respiration was low. It is evident, therefore, that there may be 
increased catalase activity without an increase of respiration. 
TABLE XX 
CATALASE pela OF AFTER-RIPENED AND DESICCATED SEEDS, 
0. 30 (CALCULATED DRY WEIGHT 0.0696) 
Treatment 0: cc. ——- after 
es pan veg ae tS hg ok 33 
SUE ON REN is oi ie ying yy sik te 28 
Strong desiteation ASR UA Ue RT 32 
Secotd imbibition. is) ins 36 
ox : 
‘ RATE AND PERCENTAGE OF GERMINATION.—Juniper seeds 
/germinate most readily at the low temperature of 5°C. These 
j 
/ 
| 
' seeds germinate, although very slowly, at o#1°C. They also 
germinate at 10°C. Seeds after-ripened at 5° C. and then placed 
at 10° C. germinated slower than those left at 5° C. After-ripened 
seeds were thrown into a state of secondary dormancy by exposure 
to temperatures above 12°C. Their catalase activity gradually 
decreased and germination ceased. After being thrown into 
secondary dormancy, several weeks at 5°C. were required to 
after-ripen the seeds again. The seeds which sank in water gave 
\ between 75 and 80 per cent germination at 5° C. 
GROWTH OF SEEDLING.—Table XXI gives the rate and extent 
of growth for seedlings exposed to the light or the dark at different 
temperatures. All seeds were germinated at 5° C. and then trans- 
ferred to the different temperatures. The length of the extending 
hypocotyl at the time of transfer was o-1mm. The seedlings 
grew the longest and fastest at 25°C. At 30°C. they never attained 
