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Title: Development, dormancy, germination and ex-situ survival of seeds of selected Amaryllidaceae species
Author: Newton, Rosemary Jean
ISNI:       0000 0004 2736 8745
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2011
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Seed development, dormancy, germination, desiccation tolerance and survival ex-situ were studied in selected members of the Amaryllidaceae following reports of poor seed germination and storability. Seed dry weight accumulation of temperate woodland European Galanthus nivalis L. and Narcissus pseudonarcissus L. continued until seed dispersal with no subsequent maturation drying phase. Seeds shed at high moisture contents (> 60% FWB). In both species, the ability of seeds to germinate developed before the ability to tolerate desiccation; the latter was not acquired in some seeds at dispersal. Embryo elongation occurred during seed development which continued post-shedding, more rapidly at warmer temperatures similar to summer temperatures of the natural post-shedding environment. Warm temperatures alleviated physiological dormancy gradually; germination occurred in most seeds at subsequent cooler, autumn-like temperatures. This pattern was repeated in seeds which did not germinate initially. Constant temperatures and darkness promoted germination in both species, with darkness a strong requirement for G. nivalis. Desiccation increased dormancy in a proportion of N pseudo narcissus seeds. Seeds 'of European Leucojum aestivum L. and N pseudo narcissus and American Rhodophiala bagnoldii (Herb.) Traub, Rhodophiala advena (Ker Gawl.) Traub and Zephyranthes drummondii D.Don tolerated drying to 4.1 - 5.5% moisture content. Seeds of the American and European species survived sub-zero storage for over four years and six months respectively, and are probably orthodox. Galanthus nivalis seed survival on desiccation varied considerably amongst populations: virtually no seeds survived drying to 7.1 - 7.3 % moisture content while others tolerated desiccation to 12 -18%, suggesting possible intermediate seed storage behaviour. Seeds of these American and European species are estimated to be relatively short-lived in seed bank storage compared with species from other families. Storage of seeds of European species at slightly higher moisture contents may reduce the rate of viability loss.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available