Monitoring spatial and temporal carbon dynamics in the plant soil system by co-registration of Magnetic Resonance Imaging and Positron Emission Tomography for image guided sampling

Individual plants vary in their ability to respond to environmental changes. The plastic response of a plant enhances its ability to avoid environmental constraints, and hence supports growth, reproduction, and evolutionary and agricultural success.

Major progress in the analysis of above- and belowground processes on individual plants has been made by the application of non-invasive imaging methods including Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET).

MRI allows for repetitive measurements of roots growing in soil and facilitates quantification of root system architecture traits in 3D. PET, on the other hand, opens a door to analyze dynamic physiological processes in plants such as long-distance carbon transport in a repeatable manner. Combining MRI with PET enables monitoring of short livedCarbon tracer (¹¹C) allocation along the transport paths (i.e. roots visualized by MRI) into active sink structures.

To analyse the link between root-internal C allocation patterns and C metabolism in the rhizosphere, we are combining ¹¹CO₂ with stable ¹³CO₂ labelling of plants. Isotope ratio mass spectrometry (IRMS) analyses of rhizosphere soil is applied to link root-internal C allocation patterns with distribution of ¹³C in the rhizosphere soil. The metabolically active rhizosphere organisms are subsequently identified based on DNA ¹³C stable isotope probing.

In our presentation we will highlight our approaches for gathering quantitative data from both image-based technologies in combination with destructive analysis that provides insights into the functioning and dynamics of C transport processes in the plant-soil system.