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 o r threatened dryland palms Hyphaene thebaica, H, petersiana and Medemia arg un is assessed. Seeds of all three species had mean emergence times of 23 t o 52 d on 1% agar-water at 26 degrees C. Soaking seeds in water reduced eme rgence times by 21 to 56%. Within species, low electrical conductivity of t he steep water was not a reliable indicator of germination potential. Seeds were long-lived in dry warm storage (+/- 21 degrees C and +/- 55% RH); som e 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 lo w RH (+/- 21-30%) or susceptibility to -20 degrees C freezing. The latter r esponse was rapid (7 d). The results indicate that the seed conservation of these species under conventional seed bank conditions is not yet guarantee d for all seeds in the population.