Abstract
Long-term seed viability is of crucial
importance for short-lived species, since persistent seed banks can buffer the
fluctuations in the establishment of plants from year to year. Temporarily
flooded habitats are an unpredictable environment for plants, and for some
species the only chance they have of surviving is the formation of persistent
seed banks. Astragalus contortuplicatus is an annual species of
periodically flooded habitats and is considered an endangered species in
Hungary. Altogether 1993 seeds of this species were tested in a germination
experiment: 1200 were freshly harvested and 793 were collected from herbarium
specimens of various ages. Seed viability was tested using the germination
method. The freshly harvested seeds were used for selecting the best out of
seven frequently used dormancy-breaking methods for this species. The highest
percentage of germination was recorded for the combined treatment of
scarification and light. Thus, this method was used to test the viability of
the seeds collected from herbarium specimens. The oldest seeds that germinated
were 131 years old. Until now there are no records of seeds of herbaceous
legumes germinating that are more than 100 years old. This record is the 9th
oldest of all the literature records of viable seeds originating from
biological collections. All the seeds that germinated developed into healthy,
fertile plants, the seeds of which also readily germinated. Fitted linear
regression showed a significant negative relationship between seed age and
percentage germination. Based on this linear regression the calculated
theoretical maximum viability is 309 years. Our results suggest that seeds of A.
contortuplicatus stored in collections can be successfully used in this
species’ reintroduction for conservation purpose, to areas in which the plants
were collected.
Keywords
biological collections, Fabaceae, hard
seeds, herbarium, Hungary, physical dormancy, scarification, persistence, seed
longevity, seed storage
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