Preservation Technology
Seed of Dactylorhiza fuchsii (Orchidaceae), which show sub-zero temperature sensitivity (Photo: C. Wood)
Conventional (orthodox) seed bank storage involves sealing dried seeds (4-7% moisture content) within air-tight containers and placing them at low temperature (-20°C). Routine germination tests are carried out in order to ensure that the collections maintain a high level of viability. Under these storage conditions it is predicted that seeds of many species will remain viable for many decades, if not hundreds or even thousands, of years. However, as this potential difference in longevity is of one or two orders of magnitude; a continued focus of this sector will be identifying taxa (at the family- / genus-level) which are particularly short-lived (in order to advise on re-testing schedules) and looking for correlates / predictors of relative longevity (e.g. seed composition, seed size / structure, habitat, distribution, climate).
Storage at a wider range of moisture contents and temperatures [including long-term, low-temperature (sub-zero down to LN2) storage experiments] will provide confirmation (or otherwise) that relative (comparing across taxa) seed longevity does not significantly differ with storage environment. This will enhance our understanding of how these two variables determine seed longevity, and provide further information on optimum storage conditions for maximising seed longevity. Since moisture sorption relations and how they change with temperature (e.g. ageing cf. seed bank storage) are fundamental to our understanding of what metabolic processes (e.g. ageing, repair) may take place, accurate determination of seed equilibrium relative humidity and moisture content is a vital component of this sector’s work.
Whilst the MSBP has been primarily focused on the storage of orthodox seeds, cryobiological studies will be carried out on species with desiccation-sensitive seeds. The development and transfer of cryobiological conservation methodologies is a component of the Global Strategy for Plant Conservation.
Contact: Dr Jayanthi Nadarajan
See the Science Directory for a full list of projects included in this Theme
