Abstract Detail

Paleobotany

Developing appropriate paradigms for assessing the plant-fungal fossil record.

The majority of the fossil record of plant-microbial interactions is heavily tilted to permineralized plant assemblages, comparatively rare paleobotanical lagerstätten where plant remains are fossilized in three dimensions at a cellular level of detail. That all permineralized assemblages are in fact wetland assemblages is a critical and as-yet neglected facet in paleoecologial investigation of plant-fungal interactions. Wetland (hydric) soils are biogeochemically hostile environments primarily controlled by microbially-mediated reduction-oxidation (redox) dynamism, affecting bioavailability of key plant nutrients. Redox dynamism is unparalleled in subaerial systems where major ecological hypotheses for plant-fungal interactions have been developed. Despite being biased towards plants living in/near hydric soils, the fossil record of plant-microbe interactions has been consistently interpreted in accordance with models of plant-microbe interaction developed in subaerially-exposed soil systems. Such paleoecological inferences can be better contextualized by studying biogeochemically-appropriate modern analogues for fossil wetland assemblages. For instance, mycorrhizal fungi of wetland plants may exhibit host plant specificity, whereas endophytes may not, suggesting alpha diversity of endophytic fungi within a fossil assemblage could be ascertained through investigation of several abundant rooting structures regardless of host plant identity, whereas mycorrhizal components would benefit from a more targeted approach. Similarly, understanding the extent to which spore bank and plant tissue fungal communities are congruent, and whether modern wetland root mycobiomes are geographically dispersed, offers opportunities to extrapolate probable fungal beta diversity for key geologic intervals, i.e., beyond individual fossil assemblages. In addition to providing a new lens through which to examine the fossil record of plant-fungal interactions, these investigations can simultaneously establish a framework for future ecological investigations of contemporary wetlands.

1 - University Of Manitoba, Biological Sciences, 50 Sifton Road, Winnipeg, MB, R3t 2M5, Canada

Keywords:
plant-microbe interactions
wetlands
paleomycology
mycology
biogeochemistry
hydric soils.

Presentation Type: Oral Paper
Number: PB5003
Abstract ID:745
Candidate for Awards:None