The germination of Datura ferox seeds is blocked immediately after ripeness by an inhibitor. The decoating of the seeds and certain storage conditions promote germination by favoring the diffusion of the inhibitor or its destruction.Seeds in which the germination blockage due to the inhibitor had been overcome behave as photoblastically positive, responding to the R–FR mechanism. During afterripening, the capacity of the skotomechanism increases as the inhibitor level decreases. The skotomechanism blockage does not disappear with low temperature or with alternating temperatures. On the other hand, high temperature reimposes this blockage.Gibberellic acid replaces the effect of red light, whereas thiourea is not effective.It is postulated, on the basis of the results obtained with this species, and the results of other authors, that the quantity of an oxidation product present, resulting from metabolic processes during storage or the action of red light, controls both germination and the possibility of germination being produced in conditions of light or darkness.

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