OutLabMRI

Forest and grassland are the two main terrestrial ecosystems able to mitigate global warming thanks to their high capability to store carbon. Ascendant (xylem) and descendant (phloem) sap flows play a key role in this storage by routing the water necessary for the oxygenic photosynthesis and then transporting the assimilated carbon into the carbon sinks, e.g. wood, roots or soil. In the current context of global warming, a better understanding of these transport mechanisms is key to ensure these ecosystems can continue to play their carbon sink role. Unfortunately, no sensor allowing studying these mechanisms directly in the plant and in its natural ecosystem exists yet. In this project, we will set and validate a new versatile MRI instrument to measure locally and non-invasively water content and flow rate outside the laboratory (in situ). This approach allows exploiting the unique and advantageous features of MRI: it is non-invasive, can measure water quantities and flow rates and is spatially selective, i.e. measurements can be performed in well-defined plant areas. The aim of this project will be to validate this instrument as a new tool to study both forest and grassland agro-ecosystems. For each of them, we will demonstrate the advantages of this new sensor relatively to the in-situ reference methods (such as lysimeters, sap flow sensors, gravimetric methods …). This instrument will be evaluated in regards of its capabilities to: (1) give localized information (specificity), especially to measure both xylem and phloem sap flows as they do not go through the same cells in plants and, to discriminate the root heterogeneity directly in the soil; (2) perform measurements under several environmental conditions (sensibility). We will focus on the hydric stress in order to detect cavitation in trees and recovery of grasses (3) evaluate the carbon storage by the ecosystems thanks to sugar concentration measurements by the in-situ MRI instrument. To maximize the success rate of this project, a multi-disciplinary team has been gathered. The skills of the scientists involved are going from vegetal physiology to applied mathematics through ecosystem modelling. Furthermore, Carel Windt, an internationally renowned scientist for his skill to develop in-situ MRI sensor, will follow the project and bring his expertise to the scientific discussions and choices. At the end of this project, the interest of this new sensor will have been demonstrated and its deployment at larger scale, to have a better understanding of the carbon storage mechanisms, will be possible. The following step would be to create a network of in-situ MRI instruments. Thus, measurements at the individual level would bring more knowledge on the plant itself while exploiting the network data would lead to a better understanding of the whole plant community as an ecosystem. Furthermore, new applications could be tested, especially in microfluidic sciences or in bio-based industries, two fields having currently a high gross rate. To disseminate as widely as possible our results, we will communicate to several scientific communities which could be interested by our results (MRI, functional ecology), to the public thanks to vulgarization (scientific days, articles in scientific magazine). Furthermore, we will make available the instrument to the scientific community through dedicated networks like AnaEE.