Seed Dormancy inAcer pseudoplatanusL.: the Role of the Covering Structures

Publisher Website
Google Scholar
Abstract
The present studies with Acer pseudoplatanus L. suggest that the covering structures play an important and multiple role in the dormancy of the fruit. Whole fruits and seeds with the testa intact required a period of chilling at 5 °C before dormancy was broken whereas bare embryos germinated immediately at 20 °C without pretreatment. This suggested that dormancy was coat-imposed and that the testa was responsible for this effect. Germination of dormant seeds was inhibited by light whereas the non-dormant bare embryos showed little response. Studies on the manner in which the testa imposed dormancy on the embryo indicated that restriction on oxygen uptake, water uptake, mechanical restriction to embryo enlargement, and the presence of germination inhibitors in the testa were not limiting factors at this stage of dormancy. Results from leaching experiments suggest that dormancy was the result of the restriction by the testa of the outward diffusion of a germination inhibitor(s) present in the embryo. In seeds that had nearly completed their stratification requirements, the covering structures seemed to act in a manner other than by preventing the leaching of an inhibitor from the embryo. At this point the physical properties of the covering structures seem to determine any further delays in germination by the mechanical restriction of embryo enlargement by the testa and by restriction of oxygen uptake by the pericarp.

This publication has 0 references indexed in Scilit: