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Contributed Talk

Session: : Environmental Gradients

COS 284-2 - Root traits vary more than leaf traits among populations in a globally widespread herb

Thursday, August 10, 2023
1:45 PM – 2:00 PM PDT
Location: E142
Abstract: Our understanding of plant functional trait variation among populations and how this relates to local adaptation to environmental conditions is largely shaped by aboveground traits. Above- and belowground traits are also phenotypically plastic in response to altered biotic and abiotic growing conditions, and the strength of these responses might also vary among populations. We used populations of a globally widespread herb - Plantago lanceolata- within the PlantPopNet project to assess the strength of among-population variation in belowground traits, whether this variation is linked to source environment conditions, and whether populations differ in their ability to respond to changes in water availability and presence of soil symbionts (arbuscular mycorrhizal fungi). The source environments of these populations varied in mean annual temperature, mean and seasonality of soil moisture. In a glasshouse experiment, we grew Plantago plants from seed for 14 populations from three continents, and measured leaf and root traits linked to resource acquisition and water conservation. Plants were exposed to two sets of experimental treatments: high or low water availability; arbuscular mycorrhizal fungi (AMF) inoculation or no inoculation. We used principal component analysis (PCA) to capture and assess variation among traits. Across treatments, the percentage of explained root trait variation resulting from populations and continents tended to be greater (47–-70%) than for explained leaf trait variation (16–-54%). The root trait PC 2 was negatively related to mean annual temperature and positively related to mean moisture content, indicating that populations from cooler, wetter environments had longer, thinner roots. However, we found little support for a relationship between source environment and any other principal component, and individual root or leaf traits. There was no evidence that effects of water availability and AMF inoculation on traits varied among populations. This globally widespread herbaceous perennial has a clear signal of population-level variation in a suite of root traits, but that variation is only partially linked to source environments. Despite considerable source environment differences, distant populations have retained a strong capacity for phenotypic plasticity both above- and belowground. Further work is needed to assess how root trait variation relates to soil symbionts in source environments.