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Multi-year sampling provides insight into the bet-hedging capacity of the soil-stored seed reserve of a threatened Acacia species from Western Australia

  • Anne CochraneEmail author
Article
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Abstract

This multi-year study examined temperature requirements for dormancy release in physically dormant seeds of the threatened legume Acacia awestoniana (Fabaceae) from Western Australia. Seeds were collected from a single site in three consecutive years and exposed to multiple laboratory-based ‘fire’-related temperature treatments (intensity × duration). Experiments were conducted on seeds freshly collected and after 12 months storage under dry laboratory conditions in order to separate the influence of the maternal environment from post-harvest storage conditions on thresholds for dormancy release. Initial seed viability and non-dormant seed fraction did not differ between seed cohorts but there was a clear effect of storage on seed response: fresh seeds from 2016 demonstrated greater thermal resilience than stored seeds collected in the same year. Equally, there was a strong inter-annual response to treatments from fresh seeds collected in 2016 and 2017 attributed to the influence of the maternal environment during seed development. Seeds collected in 2015 and 2016 and stored for 12 months also demonstrated significant differences in their response to treatments, with 2015 seeds responding more favourably to treatment conditions than those from 2016. Plastic responses to external stimuli provide seeds with a strong bet-hedging capacity and the potential to cope with high levels of environmental heterogeneity, especially a mosaic of fire conditions. Such data provide insight for the management, conservation and restoration of this and similar threatened plant species in fire-prone ecosystems in the face of a rapidly changing climate and expected associated changes in the fire regime.

Keywords

Physical dormancy Hard-seededness Seed germination Transgenerational plasticity 

Notes

Acknowledgements

My thanks to Dr. Sarah Barrett and Dr. Tony Friend for assistance with seed collection, to Dr. Matt Williams for advice on statistics and to two anonymous reviewers for their helpful comments and suggestions.

Compliance with ethical standards

Conflict of interest

The author declares no conflict of interest.

Supplementary material

11258_2019_909_MOESM1_ESM.docx (14 kb)
Supplementary file1 (DOCX 15 kb)

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© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.Biodiversity and Conservation ScienceDepartment of Biodiversity, Conservation and AttractionsKensingtonAustralia
  2. 2.Division of Ecology and EvolutionAustralian National UniversityCanberraAustralia

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