Differential ageing responses of seeds of wild Australian plant species under open versus hermetic conditions

Understanding how storage conditions and seed traits impact the lifespan of seeds is important for the curation of banked seed collections. Storage temperature, seed moisture content and oxygen are factors known to influence seed longevity. Rapid ageing — storing seeds under high temperature and moisture conditions — is used to identify shorter- or longer-lived seeds in a shortened timeframe. Rapid ageing is conducted in either open or hermetic storage conditions; the former being commonly used for efficiently studying the longevity of large numbers of diverse species, for example to improve curation practices for seed banks conserving wild plant species. However, these open storage conditions differ from the hermetic environments typically used in seed banking, particularly in terms of oxygen availability. We investigated the longevity of seeds of 13 wild Australian plant species rapidly aged for up to 236 days at 45°C and 60% RH under both open and hermetic conditions. We found differential responses to the storage conditions amongst species. Seeds of three species aged faster in open storage, four species aged faster in hermetic storage, while the remaining species showed similar ageing rates in both conditions. The methodology for rapid ageing of seeds should be considered if the purpose is to inform genebank management where seeds are commonly stored hermetically.