Seed storage and germination of the palms Hyphaene thebaica, H. petersiana and Medemia argun

The potential for ex situ seed conservation of the economically important or threatened dryland palms Hyphaene thebaica, H. petersiana and Medemia argun is assessed. Seeds of all three species had mean emergence times of 23 to 52 d on 1% agar-water at 26°C. Soaking seeds in water reduced emergence times by 21 to 56%. Within species, low electrical conductivity of the steep water was not a reliable indicator of germination potential. Seeds were long-lived in dry warm storage (± 21°C and ± 55% RH); some germinability was retained after 2-5 y. Some seeds (no more than 15 to 60%) of all three species exhibited either a sensitivity to desiccation to low RH (± 21-30%) or susceptibility to -20°C freezing. The latter response was rapid (7 d). The results indicate that the seed conservation of these species under conventional seed bank conditions is not yet guaranteed for all seeds in the population.