Abscisic acid and the regulation of embryo dormancy in the genus Acer

Abstract

Germination of Acer pseudoplatanus L. and Acer platanoides L. seeds was increased by moist storage of the intact fruits (seed + pericarp) at 5 degrees C, but not at 17 degrees C. In both species, germinative capacity of isolated embryos (seeds with testa removed) was increased by moist storage of fruits at either 5 or 17 degrees C. Thus dormancy loss by intact seeds and excised embryos was not necessarily correlated. Loss of dormancy in isolated embryos was associated with a reduction in free abscisic acid (ABA) content. Embryos from freshly harvested fruits of A. pseudoplatanus had a higher germinative capacity and a lower free ABA content than embryos from freshly harvested fruits of A. platanoides. Morever, germinative capacity increased, and free ABA content decreased, more rapidly with length of fruit storage in A. platanoides embryos than in A. pseudoplatanus embryos.