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Abstract Detail

Time to dig: the importance of underground storage organs in plant evolution

Jantzen, Johanna [1], Soltis, Douglas [2], Soltis, Pamela [3].

The role of xylopodia in the evolution of Tibouchina s.s. (Melastomataceae).

Tibouchina s.s., a clade of flowering plants in the Melastomataceae, is found predominantly in open savanna habitats, with high levels of species diversity and endemism in the cerrado and campos rupestres of Brazil. Xylopodia, woody underground bud banks, are commonly found in the plants of the cerrado and campos rupestres, including Tibouchina s.s., and represent adaptations to the frequent fires that characterize these ecoregions, allowing for rapid regeneration and long-term persistence. It has been hypothesized that the diversification of plants within these ecoregions may have been triggered by adaptations to fire, such as xylopodia. To determine the role that xylopodia may have played in the evolution of Tibouchina s.s. within the cerrado and campos rupestres, we determined the prevalence of xylopodia within this clade, and identified morphological variation within this structure for the thirty species of Tibouchina s.s. We determined that xylopodia are found universally among Tibouchina s.s. and that morphological variation is linked to soil substrate. The presence of xylopodia likely allowed for the persistence of Tibouchina s.s. within the cerrado and campos rupestres, enabling it to diversify within these ecoregions. Using a well-sampled phylogeny for Tibouchina s.s., we identified a shift in diversification rate linked to the transition from regions that do not experience frequent fires to the fire prone cerrado and campos rupestres, potentially indicating a facilitative effect that adaptation to fire may have played in the diversification of this clade.

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1 - University Of Florida, Biology, Dickinson Hall, 1659 Museum Road, Gainesville, FL, 32611, United States
2 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611, USA
3 - University Of Florida, Florida Museum Of Natural History, Po Box 117800, Gainesville, FL, 32611, United States

Campos rupestres

Presentation Type: Colloquium Presentations
Session: CO07, Time to Dig: the importance of underground organs in plant evolution.
Location: Tucson J/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 9:30 AM
Number: CO07004
Abstract ID:576
Candidate for Awards:None

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