Carlos A Ordóñez-Parra, Natália F Medeiros, Roberta L C Dayrell, Soizig Le Stradic, Daniel Negreiros, Tatiana Cornelissen, Fernando A O Silveira
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引用次数: 0
Abstract
Background and aims: Rock outcrop vegetation is distributed worldwide and hosts a diverse and unique flora that evolved under harsh environmental conditions. Unfortunately, seed ecology in such ecosystems has received little attention, especially regarding seed traits, germination responses to abiotic factors and the potential role of phylogenetic relatedness on such features Here, we provide the first quantitative and phylogenetically-informed synthesis of the seed functional ecology of Brazilian rock outcrop vegetation, with a particular focus on quartzitic and ironstone campo rupestre.
Methods: Using a database of functional trait data, we calculated the phylogenetic signal of seven seed traits for 371 taxa and tested whether they varied among growth forms, geographic distribution, and microhabitats. We also conducted meta-analyses that included 4,252 germination records for 102 taxa to assess the effects of light, temperature, and fire-related cues on the germination of campo rupestre species and explored how the aforementioned ecological groups and seed traits modulate germination responses.
Key results: All traits and germination responses showed a moderate-to-strong phylogenetic signal. Campo rupestre species responded positively to light and had maximum germination between 20-25 ºC. The effect of temperatures beyond this range was moderated by growth form, species geographic distribution, and microhabitat. Seeds exposed to heat shocks above 80 °C lost viability, but smoke accelerated germination. We found a moderating effect of seed mass for in responses to light and heat shocks, with larger, dormant seeds tolerating heat better but less sensitive to light. Species from xeric habitats evolved phenological strategies to synchronise germination during periods of increased soil water availability.
Conclusions: Phylogenetic relatedness plays a major role in shaping seed ecology of Brazilian rock outcrop vegetation. Nevertheless, seed traits and germination responses varied significantly between growth forms, species geographic distribution and microhabitats, providing support to the regeneration niche hypothesis and the role of functional traits in shaping germination in these ecosystems.
期刊介绍:
Annals of Botany is an international plant science journal publishing novel and rigorous research in all areas of plant science. It is published monthly in both electronic and printed forms with at least two extra issues each year that focus on a particular theme in plant biology. The Journal is managed by the Annals of Botany Company, a not-for-profit educational charity established to promote plant science worldwide.
The Journal publishes original research papers, invited and submitted review articles, ''Research in Context'' expanding on original work, ''Botanical Briefings'' as short overviews of important topics, and ''Viewpoints'' giving opinions. All papers in each issue are summarized briefly in Content Snapshots , there are topical news items in the Plant Cuttings section and Book Reviews . A rigorous review process ensures that readers are exposed to genuine and novel advances across a wide spectrum of botanical knowledge. All papers aim to advance knowledge and make a difference to our understanding of plant science.