Identifying long-lived and short-lived seeds

Some seeds are longer-lived than others and there is good evidence from a number of sources that some seeds can remain alive for hundreds of years. Although most seeds will survive for many decades under very dry and cold seed bank conditions, there are differences between species.

Equipment used in controlled ageing tests at the MSB RBG Kew

Mathematical models suggest that seed longevity under seed bank conditions varies from a few decades for the shortest-lived species to over a thousand years for the longest-lived. One of the challenges for seed conservationists is knowing which species will be long-lived and which will be short-lived. MSBP scientists have been using controlled ageing tests to provide some clues.

Samples of seeds from collections in the seed bank are ‘aged’ by placing them in sealed containers under warm (45°C) and humid (60% RH) conditions. Just as dry and cold conditions prolong seed storage life, so warm and humid conditions cause seeds to age rapidly.

Samples of aged seeds are withdrawn at intervals and are germinated to see if they are still alive. The results are compared with the longevity of ‘marker’ species of known longevity such as Ranunculus sceleratus L. (celery-leaved buttercup) and Brassica napus L. (oil seed rape) under the same conditions.

From this research on over 200 species representing over 70 plant families we have learnt that seeds with small embryos from plants that grow in cool, moist environments are more likely to be short lived compared to seeds with large embryos that come from warmer drier regions.

Further information

Probert, R.J., Daws, M.I. & Hay, F.R. (2009) Ecological correlates of ex situ seed longevity: a comparative study on 195 species. Annals of Botany 104, (1), 57–69.