Patterns of root intraspecific trait variability

• Applicant: Professor Matthias C. Rillig, Ph.D.
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 378189215

Plant trait-based approaches are becoming increasingly important in ecological research. During the last years, scientists have begun to also consider intraspecific trait variability (ITV) when working with trait-based approaches. ITV consists of genetic variation within the species or population and phenotypic plasticity along environmental gradients. Nevertheless, the relative impact of these two factors to total ITV has to our knowledge never been studied in detail. Another scarcity of plant trait based research is the lack of root traits. Especially when studying soil ecological effects on plant, community or ecosystem performance roots are promising to hold more direct information than traditionally measured aboveground traits. Our aim is to study intraspecific root trait variability and its components in an experimental setup ranging from a highly mechanistic approach in climate chambers to field sampling in a natural grassland with strong small scale soil environmental gradients. We will investigate root ITV in one grass species (Arrhenatherum elatius P.BEAUV) and one forb species (Achillea millefolium L) from the natural reserve Mallnow (Brandenburg, Germany). We will mimic several soil environmental factors including drought, pH, nutrient deficiency and soil structure with varying levels (in agar) and measure root trait expression on different clones cultivated from seeds of the same population. This will give us information about root trait expression under different soil environmental conditions and allow us to quantify both genetic variation as well as phenotypic plasticity within a natural population. Furthermore we will experimentally combine soil environmental factors to study interactive effects on root trait expression. In a field experiment we will sample soil factors and trait expression of the target population in the natural context. Genotyping of the experimental clones as well as the plants sampled in the field will allow us to combine our knowledge on individual phenotypic plasticity with occurrence in the natural ecosystem. This approach will enable us to draw conclusions about the relative amount of genetic variation and phenotypic plasticity on total ITV found under different levels of environmental stress in the field. We aim to incorporate our findings into the framework of ecological niche theory by calculating trait hypervolumes and modeling the effects of ITV and its components. This project will contribute to the ongoing process of better understanding the importance of ITV and support the incorporation of root traits into trait-based ecology.

• DFG Programme: Research Grants