Nov. 1,1925 
Stimulating Germination of Western White-Pine Seed 899 
ducted with Pinus sylvestris at Eberswalde 5 and elsewhere, prove 
that a temperature above 115° F. is undesirable, particularly because 
of the greatly increased heating capacity of the moister air within 
the cones. The seed used in these experiments has been extracted 
promptly under temperatures below 90° F. and preserved from any 
other possible injury. 
SUMMARY 
This investigation has indicated that the delayed germination of 
western white-pine seed is not caused by any inherent physiological char¬ 
acteristic of the seed embryo or endosperm, such as after-ripening or 
the need for a period of rest, but by the impermeability of the seed 
coat, and that prompt germination may be obtained from unimpaired 
fresh seed by any of the following methods: 
(1) Reduction of the seed coat by chemical corrosion, preferably 
by immersion for 45 minutes in concentrated sulphuric acid with 
thorough rinsing. 
(2) Reduction of the seed coat by a mechanical abrasion or pearling 
process in such a manner that the seed is not cracked or subjected to 
much pressure. 
(3) Soaking the seed in cold water for 24 hours and exposing it to 
air freezing in winter for at least 40 days. 
(4) Burying the seed in moist bark-free sawdust, and maintaining 
it at a relatively warm temperature for three weeks, followed by 
immediate sowing. 
In the absence of preliminary treatment, good germination may 
result from late fall sowing of good, newly collected seed, but rainy 
winter weather with temperatures above freezing may cause the seed 
to decay. 
i HAACK, —. ttBER DIE KEIMUNG UND BEWERTUNG DES KIEFERSAMENS NACH KEIMPROBEN. ZtSChr. 
Forst u. Jagdw. 38: 441. 1906. 
74333—26f-8 
o 
