THE SEED COAT EFFECT IN RELATION TO THE PHOTOINDUCTION OF GERMINATION IN DATURA FEROX L.

Abstract

In decoated photoblastic Datura ferox seeds, the length of the incubation period which precedes irradiation with red light affects their response to this treatment. Although the behavior of intact seeds shows the same tendency, the germination counts do not reach the same values. These differences between intact and decoated seeds decrease as afterripening advances.The presence of the seed coat during the incubation period which precedes irradiation brings about a situation which can, depending on the stage of after-ripening, determine a decrease in the response to photoinduction.As afterripening advances, the light requirement for maximum response decreases, as does the level of the inhibitor present in the seeds.The changes in response obtained when seeds are incubated intact or decoated in different stages of afterripening may be linked to either of these phenomena. The physiological situations revealed by the experimental results, and which appear to be related to the presence or absence of the seed coat, may be due to its effect on oxidation processes.