Seed quality for conservation is critically affected by pre-storage factors
Robin Probert A C , John Adams A , Julia Coneybeer A , Andrew Crawford B and Fiona Hay AA Seed Conservation Department, RBG Kew, Wakehurst Place, Ardingly, West Sussex, RH17 6TN, UK.
B Science Division, Department of Conservation and Land Management, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia.
C Corresponding author. Email: r.probert@kew.org
Australian Journal of Botany 55(3) 326-335 https://doi.org/10.1071/BT06046
Submitted: 14 March 2006 Accepted: 17 August 2006 Published: 18 May 2007
Abstract
The quality of seed-conservation collections, and hence their value for species reintroduction or restoration, is critically dependent on factors operating in the period between the point of collection and arrival at environmentally controlled processing and storage facilities. The timing of the acquisition of desiccation tolerance and seed longevity in air-dry storage, in relation to mass maturity and the time of natural seed dispersal, varies across species. In some wild plant species, seed quality continues to improve up to, and possibly beyond, the point of dispersal. Holding immature berries of Solanum dulcamara L. and capsules of Digitalis purpurea L. under natural conditions enabled comparison of seed quality between seeds stored under natural conditions and those dried rapidly under seedbank dry-room conditions. While seeds from fully ripe (post-mature) capsules of D. purpurea were insensitive to different post-harvest drying treatments, seed quality declined when mature berries of S. dulcamara were held under natural conditions. These results emphasise that the selection of post-harvest treatment will not only depend on the maturity of collected seeds but also may vary across species depending on the fruit type. Except for subtropical and tropical coastal locations, ambient daytime conditions during the main seed-collecting season (November–February) across Australia can be expected to result in tolerable rates of seed deterioration for the duration of seed-collecting missions. However, because seed moisture levels can be considerably higher than when equilibrated with ambient relative humidity, post-harvest handling decisions should ideally be informed by measurements of seed moisture at the time of collection, and subsequently seed moisture should be monitored during transit.
Acknowledgements
This work was conducted under the auspices of the Millennium Seed Bank Project Kew, which is supported by the UK Millennium Commission, the Wellcome Trust and Orange plc.
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