In vivo quantification of carbon allocation in plant root networks

Project Topic: Understanding and Modeling Carbon Transport in Plants Using PET Imaging and Computational Simulation

How do plants move carbon from where it is produced to where it is needed? Understanding this question is key to improving plant resilience and productivity in changing environmental conditions, for example, under heat, drought, or limited light. However, studying the internal flow of carbon within plants is a challenging task, especially because one of the main transport systems, the phloem, is highly sensitive and difficult to observe directly.

This project aims to develop new tools and methods to better understand how carbon is transported through plant roots and shoots. We use a highly specialized imaging technique called positron emission tomography (PET), which allows us to follow the movement of a short-lived radioactive tracer (¹¹C) inside the plant. PET is unique in that it provides real-time, 3D information about how carbon moves through living tissues without harming the plant. At Forschungszentrum Jülich, PET measurements can be combined with structural imaging such as magnetic resonance imaging (MRI) to gain a more complete picture of internal plant architecture and function.

To create knowledge and understanding from these complex datasets, we build mathematical models that simulate carbon transport in the plant. These models are implemented in CADET, a modern, open-source simulation platform originally developed for process engineering. CADET now also supports modeling of biological systems and is used by researchers around the world. Our models allow us to extract important physiological information such as transport speed, storage capacity, and branching behavior in roots and other plant parts.

The next step — and the main focus of this project — is to extend the current modeling framework to represent branched transport networks like full root systems. So far, most models have focused on straight or simplified transport pathways. However, in reality, plants have complex, branched structures that influence how carbon is distributed. The new model will enable an analysis of carbon transport throughout the entire root system, and even the whole plant, using a network-based approach.

In addition, we aim to move beyond static conditions. Most current models assume that the transport behavior stays constant during the measurement period (usually around two hours). But plants continuously adjust their internal processes in response to environmental changes, such as variations in temperature or light. By incorporating time-dependent parameters, the new modeling tools will enable us to study plant responses over longer periods, from minutes to weeks.

What makes this project exciting?

• You will work at the interface of plant biology, imaging, and computational modeling.

• The project combines experimental work (PET imaging of living plants) with modeling and simulation (network-based transport models in CADET).
• You will contribute to an open-source platform with a growing international community.
• The research has direct relevance for sustainable agriculture, climate resilience, and systems biology.

The outcome of this project will deepen our understanding of how plants distribute carbon under different environmental conditions — knowledge that is critical for developing more resilient and productive crops. It will also contribute to ongoing efforts to build integrated models of whole plant behavior.