Alexander Schulz receives grant from the Independent Research Fund Denmark

The project which starts on November 1^st, 2019 aims at imaging flows in leaves to identify vascular control points and to model water partitioning in response to environmental changes.

Abstract

The balance of water movement between evaporation, photosynthesis and osmotic phloem uptake is crucial in plants, since water is a limiting resource; but how this balance is regulated under changing environmental conditions is not understood. Key elements of the regulation are hidden in the leaves. We propose to uncover the flow control points by multimodal and live imaging (X-ray tomography, fluorescence and electron microscopy). By combining imaging with theoretical modelling, our goal is to understand the mechanism and efficiency of the combined vascular flow, eventually exporting sugars out of the leaves. Long conifer needles with linear venation are challenging the Münch mechanism. We aim at characterising the water and sugar flows all the way from mesophyll via the bundle sheath to the phloem, including water loss in evaporation and usage in photosynthesis. In broad leaves, we will examine the changes of the effective resistance due to their hierarchical venation structure.

Collaboration

This project continues the strong cross-disciplinary collaboration between Biology and Physics by Prof Alexander Schulz and Prof Tomas Bohr, DTU, respectively, who will supervise one PhD student each. Expertise in X-ray computed tomography and synchrotron imaging will be provided by Prof Henning Friis Poulsen, DTU. The PhD students individually and the project collectively will strongly benefit from stays and interactions in the world-leading labs for phloem loading and vascular flow modelling, led by Prof Robert Turgeon and Prof Noel Michele Holbrook at Cornell University, Ithaca, and Harvard University, respectively.

Alexander Schulz explains: 'Collaboration with the physicist and expert in fluidics Tomas Bohr has been incredibly beneficial for my approach to the fundamental question of the mechanism of sugar transport in plants. This highly ambitious project aims at understanding the circulation of water engaged in the ascent of sap into and the export of sugars from leaves. Multimodal imaging, including µCT using synchrotron beamlines, will be the key to observe processes which otherwise are hidden deep inside leaves'.

The project will start on 1 November 2019 and has a duration of 4 years.

Link to announcement.