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Heterochrony and repurposing in the evolution of gymnosperm seed dispersal units

TitleHeterochrony and repurposing in the evolution of gymnosperm seed dispersal units
Publication TypeJournal Article
Year of Publication2022
AuthorsSan Martin J.A, Pozner R.E, Di Stilio V.S
Pagination7 pages
Date Published02/2022
Type of ArticleOriginal research

Plant dispersal units, or diaspores, allow the colonization of new environments expanding geographic range and promoting gene flow. Two broad categories of diaspores found in seed plants are dry and fleshy, associated with abiotic and biotic dispersal agents, respectively. Anatomy and developmental genetics of fleshy angiosperm fruits is advanced in contrast to the knowledge gap for analogous fleshy structures in gymnosperm diaspores. Improved understanding of the structural basis of modified accessory organs that aid in seed dispersal will enable future work on the underlying genetics, contributing to hypotheses on the origin of angiosperm fruits. To generate a structural framework for the development and evolution of gymnosperm fleshy diaspores, we studied the anatomy and histochemistry of Ephedra (Gnetales) seed cone bracts, the modified leaves surrounding the reproductive organs. We took an ontogenetic approach, comparing and contrasting the anatomy and histology of fleshy and papery-winged seed cone bracts, and their respective pollen cone bracts and leaves in four species from the South American clade.

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