Seed biology of Metrosideros excelsa (Myrtaceae)

Abstract

Mature seed capsules of pohutukawa (Metrosideros excelsa) contain a mixture of filled (embryo-containing) and unfilled (embryo-lacking) seeds. Both types of seeds were characterised with respect to their dimensions, weight, viability, and their germination rate under two different storage regimes. Filled seeds have a lower length/width ratio, and are approximately 25% heavier than unfilled seeds. Treatment of seeds with 1% tetrazolium chloride at 37°C resulted in staining of all filled, but no unfilled seeds. There was no difference in the numbers of filled seeds occupying the top, centre, and basal portions of capsules, and filled seeds were randomly disposed on the placenta. The germination rate of filled seeds was 99% upon harvesting and still exceeded 90% after one year of storage at +1°C. When stored at room temperature, this rate decreased to 58% after 6 months and there was no germination after one year of storage. © 2002 Taylor & Francis Group, LLC.