Induction of cocklebur seed germination by anaerobiosis: A question about the "inhibitor hypothesis" of seed dormancy.

Germination of non-dormant small cocklebur (Xanthium pennsylvanicum Wallr.) seeds was improved by immersing them in water, suggesting that during their germination endogenous germination inhibitors are leached out. However, the same effect could be obtained by the quasi-anaerobic pre-incubation of the seeds. When seeds were fully imbibed, moreover, water immersion could no longer potentiate them to germinate, and only anaerobiosis increased the germination potential, thus raising a question against the "inhibitor hypothesis" of seed dormancy.