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Data from: defining the pyro-thermal niche: do seed traits, ecosystem type and phylogeny influence thermal thresholds in seeds with physical dormancy

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Apr 26, 2024 version files 158.06 KB

Abstract

Seeds are a key pathway for plant population recovery following disturbance. To prevent germination during unsuitable conditions, most species produce dormant seeds. In fire-prone regions, physical dormancy (PY) enables seeds to germinate after fire. The thermal niche, incorporating seed dormancy and mortality temperature responses, has not been characterised for PY seeds from fire prone environments.

We aimed to assess variation in thermal thresholds between species with PY seeds and if the pyro-thermal niche is aligned with seed mass, ecosystem type or phylogenetic relatedness.

We collected post heat-shock germination data for 58 Australian species that produce PY seeds. We applied species-specific thermal performance curves to define three critical thresholds (DRT50, dormancy release temperature; Topt, optimum dormancy release temperature and LT50, lethal temperature), defining the pyro-thermal niche. Each species was assigned a mean seed weight and ecosystem type. We constructed a phylogeny to account for species relatedness and calculated phylogenetic signal (h2) for LT50, Topt, and DRT50.

Seeds of Pomaderris (Rhamnaceae) had the highest Topt and LT50, and Pomaderris bodalla having the highest DRT50 of 101.3°C. Seeds from species within this family exhibited higher temperature thresholds than those from Fabaceae. Seed mass was only influential in explaining LT50 variation.