Abstract Detail


Charbonneau, Bianca [1], Casper, Brenda [1].

The Role of Clonal Integration in Foredune Recolonization by American Beachgrass Post-Storm.

Clonal integration can enable pioneer plants to colonize unfavorable habitats and may be particularly important in coastal foredunes, arguably the most dynamic terrestrial habitats worldwide. Storms can uproot foredune plants, creating barren, unstable blowout depressions that are ripe for recolonization. We explored the utility of maintaining persistent rhizomes in clones of American beachgrass (Ammophila breviligulata) as they expand into blowouts. In 2017 and 2018, we selected 20 rhizome pairs, equivalent spatially and of similar age as judged by size. We subjected one of each pair to an experimental treatment, where we severed the youngest most distal ramet (Plant I) from its parent (Plant II) at the beginning of the growing season. For these ramets and for an older ramet (Plant IV) on the same rhizome, we regularly measured leaf temperature and physiological stress as fluorescence (Fv/Fm), and quantified plant growth in height over the growing season. We also measured soil temperature and moisture at 15cm depth, and soil surface temperature. Post-experiment, we measured biomass, aspects of root architecture and arbuscular mycorrhizal fungi (AMF) colonization. Lastly, we tracked physiological dyes taken up by roots at a node where there was no shoot, to determine the ramets to which these roots supply water.
As expected, when there were effects of severing the rhizome connecting Plant I to older ramets, performance of Plant I decreased and performance of the older ramets increased, but not all responses were present both years. These responses include greater mortality and less shoot growth in Plant I and an increase in biomass in Plant IV, when Plant I was detached. After controlling for variation in soil temperature and moisture through ANCOVA, severed Plant I showed reduced Fv/Fm, indicating more stress, while older ramets showed increased Fv/Fm. Severing did not affect root biomass of Plant I, which both years had greater root biomass than older ramets, regardless of treatment. AMF colonization both years increased in Plant II when Plant I was detached. Roots taking up tracking dye more often supplied water to the youngest ramet but also to older ramets, even up to the 13th farthest away. These results suggest that while most young ramets, with their well-established root systems, can live independently, clones are still well-integrated. Resource sharing between older and younger ramets, enabled by clonal integration, and the production of roots without shoots may be critical to success in the stressful, dynamic foredune habitat.

1 - University of Pennsylvania, Biology, Leidy Labs, Philadelphia, PA, 19104, USA

clonal growth
coastal dune vegetation
Ammophila breviligulata.

Presentation Type: Oral Paper
Number: 0014
Abstract ID:480
Candidate for Awards:None

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