Seed Dormancy in Acer : The Relationship between Seed Dormancy, Embryo Dormancy and Abscisic Acid in Acer platanoides L.

1989

S. 313-318

4 Abb., 2 Tab., 19 Lit. Ang.

Unselbständiges Werk

200050396

Whole seeds and isolated embryos from freshly harvested fruits of Acer platanoides were deeply dormant and even excised embryonic axes from such fruits germinated poorly. Storage of fruits at inductive chilling temperatures (5C) for several weeks was necessary for the removal of dormancy from the intact seeds, but dormancy was lost from the embryo and the embryonic axis even during fruit storage at non-inductive temperatures (17C). ABA suppressed the increased germination potential that developed in embryos and embryonic axes during the early stages of post-harvest storage, but became less effective after longer storage periods, indicating a loss of sensitivity to ABA in the embryo tissue. The presence of the cotyledons following short periods of fruit storage was also inhibitory to germination of the isolated embryo and the possible role of the cotyledons as a reservoir of ABA is discussed. Endogenous ABA levels in the embryo fell markedly as a result of friut storage at either inductive or non-inductive temperatures and the speed at which this occurred is compared with the rate at which embryo dormancy was lost. It is concluded that ABA is closely implicated in the regulation of embryo dormancy in this seed, but that the breakage of dormancy in whole seeds is more dependent on other factors concerned with the presence of an intact testa.