Harnessing the power of 11C-labelling and Positron Emission Tomography (PET) for investigating Phloem velocities above and belowground

Abstract

The short-lived radioisotope 11C can be applied non-invasively to the plant as 11CO2 to follow the flow of recently fixed carbon. This method has allowed for many interesting findings on phloem flow in the past. The combination with PET detection and compartmental modelling has the potential to allow the imaging and quantification of phloem flow in complex 3D structures such as root system or branched shoots. However, this requires an experimental pipeline and facility to label and image plants in a reliable and consistent manner. We will show the key elements of the pipeline we have established in a plant-dedicated radiotracer lab for routine flow imaging along with discussing the advantages and limitation of the approach. Results will be presented on phloem flow velocities simultaneously measured in different root types of maize with statistically relevant numbers of individuals and other 3D examples. Furthermore, results will be presented on phloem flow in different parts of bean shoots and examples for other species