THE OXYGEN MINIMUM AND THE GERMINATION OF 
XANTHIUM SEEDS 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 152 
CHARLES ALBERT SHULL 
(WITH ONE FIGURE) 
Although delayed germination has received considerable atten- 
tion during the last few years from investigators both in America 
and Europe, not much has been accomplished toward solving the 
problems presented by this phenomenon. This may be due in 
large measure to lack of exact, or at least quantitative, methods 
of investigation, and to mental attitude which may modify the 
interpretation of results. Vitalistic interpretations of phenomena 
may at times prevent a close analysis of the physical and chemical 
phenomena which condition the manifestations of life, thus pre- 
venting the solution of the real problems. 
During the last two years the writer has been engaged i in an 
investigation of the relation of oxygen pressure to the germination 
of Xanthiwm seeds. The need of oxygen for germination and 
growth of organs in the higher plants has been under discussion for 
some time. TAKAHASHI (27) has shown that rice can germinate 
in complete absence of free oxygen, and CROCKER (5) has shown 
the same to be true for the seeds of certain water plants, as Eich- 
hornia and Alisma Plantago-aquatica. NABOoKIcH (20) has experi- 
mented on the hypocotyls of Helianthus annuus, Vicia Faba, and 
Phaseolus vulgaris, and concludes that the organs of higher plants 
generally are able to grow in entire absence of oxygen. A rather 
small number of species was used from which to draw sweeping 
conclusions. . LEHMANN (18) investigated the anaerobic growth of 
the organs of higher plants, and found that there is practically 
no growth in epicotyls at 1 or 2 mm. of atmospheric pressure. In 
some instances, as with Helianthus annuus, growth of the hypocotyl] 
occurred in total absence of oxygen in distilled water at a tempera- 
ture above 25°. In o.5-1 per cent sugar solution, growth occurred 
even at 20°, but was slight. A number of plants, Vicia Faba, 
[Botanical Gazette, vol. 52 
453] 
