Identifying long-lived and short-lived seeds
Some seeds are longer-lived than others. 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
Predictions 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 recognising which species will be long-lived and which will be short-lived. Controlled ageing tests can provide some clues.
Small samples of seeds from collections in the seed bank are ‘aged’ by placing them in open containers under warm (45°C) and humid (60% RH) conditions (produced by Lithium Chloride salt solutions within a sealed box). 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Samples of aged seeds are withdrawn at intervals and are germinated to see if they are still alive.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 can be compared with the longevity of ‘marker’ species such as Ranunculus sceleratus L. (Buttercup) and Brassica napus L. (Oil Seed Rape) under the same conditions.
Key Findings:
- Open storage over lithium chloride salt solution is a reliable and effective method to generate relative humidity conditions for ageing seeds.
- Species with much longer-lived and shorter-lived seeds than those already known have been identified.
- This procedure is ideal for conservation collections as it uses relatively few seeds.
Further Information:
Comparative Longevity Technical Information Sheet (pdf)