Imaging of photoassimilates transport in plant tissues by positron emission tomography

Abstract

The current findings show that positron emission tomography (PET), primarily developed for medical diagnostic imaging, can be applied in plant studies to analyze the transport and allocation of wide range of compounds labelled with positronemitting radioisotopes. This work is focused on PET analysis of the uptake and transport of 2-deoxy-2-fluoro[¹⁸F]-D-glucose (2-[¹⁸F]FDG), as a model of photoassimilates, in tissues of giant reed (Arundo donax L. var. versicolor) as a potential energy crop. The absorption of 2-[¹⁸F]FDG and its subsequent transport in plant tissues were evaluated in both acropetal and basipetal direction as well. Visualization and quantification of the uptake and transport of 2-[¹⁸F]FDG in plants immersed with the root system into a 2-[¹⁸F]FDG solution revealed a significant accumulation of 18F radioactivity in the roots. The transport rate in plants was increased in the order of plant exposure through: stem > mechanically damaged root system > intact root system. PET analysis in basipetal direction, when the plant was immersed into the 2-[¹⁸F]FDG solution with the cut area of the leaf of whole plant, showed minimal translocation of 2-[¹⁸F]FDG into the other plant parts. The PET results were verified by measuring the accumulated radioactivity of ¹⁸F by direct gamma-spectrometry.