The Effect of Temperature on the Supply of Oxygen to Embryos ofIntactAcer pseudoplatanusL. Seeds

Abstract

The effect of temperature on various factors affecting 02 supply to enclosed embryos of A. pseudoplatanus L. seeds was investigated using a simple model for 02 consumption by intact seeds. Low temperatures which induced germination had little effect on the diffusivity of the testa although an increase in diffusivity occurred immediately prior to radicle emergence. The 02 concentration surrounding an enclosed embryo was found to be 5-10% that of the solution bathing the seeds at storage temperatures. The respiratory capacity of the embryos was found to be strongly dependent on temperature and, largely as a result of this, at chilling temperatures the 02 concentration surrounding the enclosed embryo approached that in the ambient solution. The apparent Arrhenius activation energy for 02 consumption was considerably greater below 17 °C than above this temperature. Although insufficient evidence in themselves for a relationship between 02 availability and seed germination, the results do provide evidence for a mechanism by which such a relationship may be associated with seeds requiring chilling to induce germination.