The role of the covering structures in the germination of seed of Leucospermum cordifolium (Proteaceae)

Abstract

It was found that as many as half the plump, apparently healthy seed of Leucospermum cordifolium contained shrivelled embryos. Improved seed sorting to eliminate such seeds resulted in 37% germination, compared with 25% in unsorted seed. This small increase suggested that other factors may also contribute to poor seed germination. Indications are that both the outer and inner pericarps play a major role in this respect as their removal greatly increases germination. High oxygen tensions significantly increase germination of intact seed, which suggests that the covering structures exert their influence by acting as a barrier to oxygen diffusion to the embryos.