Developmental changes in relation to desiccation tolerance of Archontophoenix alexandrae （Palmae） seeds

Germination of Archontophoenix alexandrae seeds and embryos were studied under gradient water content treatments throughout the seed development phases of maturation in 2005 to investigate seed desiccation tolerance and storage characteristics. During the maturation proeess, seed water content decreased gradually from 55 DAF （days after flowering） to 70 DAF, and seeds reached the maximum dry-weight at 90 DAF. Seed germinability appeared after 60 DAF. Seeds germinated with a temperature range from 15℃-40℃ under alternating photoperiod （14 h light, 10 h dark, 12mu-mol m~(-2) s~(-1)）, while the best germination percentage was obtained between 30℃-35℃. A maximum germination capacity reached at 70 DAF. However, seed germination was greatly inhibited by light. Desiccation tolerance of seeds and embryos increased gradually from 55 DAF to 90 DAF and reached the maximum at 90 DAF with a semilethal water content of 0.18 g/ g （seed） and 0.3 g/g （embryo） respectively. Rapid dehydration maintained higher seed germination percentage than that of slow dehydration when drying to the same water content. Seeds with/without water content treatments failed to germinate after 1 month storage under -18℃, whereas appropriate desiccation treatment prolonged seed longevity under 4℃, 10℃ and 15℃ storage temperatures. It revealed obviously the recalcitrant characteristics of Archontophoenix alexandrae seed storage behaviour which are tolerant toward neither deep desiccation nor low temperatures.