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Premise of the study Theory predicts that mixed ploidy populations should be short-lived due to strong fitness disadvantages for the rare ploidy. However, mixed ploidy populations are common, suggesting that the fitness costs for rare ploidies are counterbalanced by ecological benefits that emerge when rare. We investigated whether differences in ecological interactions with soil microbes help to maintain a tetraploid-hexaploid population of Larrea tridentata (creosote bush) in the Sonoran Desert, California, USA, where prior work documented ploidy-specific root-associated microbes. Methods We used a plant-soil feedback (PSF) experiment to test whether host-specific soil microbes can alter the outcomes of intra-ploidy vs. inter-ploidy competition. Host-specific soil microbes can build up over time; thus, distance from a host plant can affect the fitness of nearby plants. Key results Seedlings grown in soils from near plants of a different ploidy produced greater biomass relative to seedlings grown in soils from near plants of the same ploidy. Moreover, seedlings grown in soils from near plants of a different ploidy produced greater biomass than those grown in soils from further away from plants of a different ploidy. This suggests the ecological consequences of PSF may facilitate the persistence of mixed ploidy populations. Conclusions This is the first evidence, to our knowledge, consistent with plant-soil microbe feedback as a viable mechanism to maintain the coexistence of multiple ploidy levels in a single population.
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Plant–soil microbe feedbacks depend on distance and ploidy in a mixed cytotype population of Larrea tridentata
Abstract PremiseTheory predicts that mixed ploidy populations should be short‐lived due to strong fitness disadvantages for the rare ploidy. However, mixed ploidy populations are common, suggesting that the fitness costs for rare ploidies are counterbalanced by ecological benefits that emerge when rare. We investigated whether differences in ecological interactions with soil microbes help to maintain a tetraploid–hexaploid population ofLarrea tridentata(creosote bush) in the Sonoran Desert, California, United States, where prior work documented ploidy‐specific root‐associated microbes. MethodsWe used a plant–soil feedback (PSF) experiment to test whether host‐specific soil microbes can alter the outcomes of intraploidy vs. interploidy competition. Host‐specific soil microbes can build up over time; thus, distance from a host plant can affect the fitness of nearby plants. ResultsSeedlings grown in soils from near plants of a different ploidy produced greater biomass relative to seedlings grown in soils from near plants of the same ploidy. Moreover, seedlings grown in soils from near plants of a different ploidy produced more biomass than those grown in soils that were farther from plants of a different ploidy. These results suggest that the ecological consequences of PSF may facilitate the persistence of mixed ploidy populations. ConclusionsThis is the first evidence, to our knowledge, that is consistent with plant–soil microbe feedback as a viable mechanism to maintain the coexistence of multiple ploidy levels in a single population.
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- Award ID(s):
- 1655499
- PAR ID:
- 10614784
- Publisher / Repository:
- American Journal of Botany
- Date Published:
- Journal Name:
- American Journal of Botany
- Volume:
- 111
- Issue:
- 8
- ISSN:
- 0002-9122
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/ajb2.16298
