Multiscale NMR investigations of two anatomically contrasted genotypes of sorghum under watered conditions and during drought stress

• Published in: Magnetic resonance in chemistry Vol. 57; no. 9; pp. 749 - 756
• Main Authors: Sidi‐Boulenouar, Rahima, Cardoso, Maïda, Coillot, Christophe, Rousset, Sébastien, Nativel, Eric, Charbit, Alain, Baptiste, Christelle, Alibert, Eric, Gatineau, Frédéric, Verdeil, Jean‐Luc, Goze‐Bac, Christophe
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.09.2019; Wiley
• Subjects: abiotic stresses in plant; Biomarkers; Condensed Matter; Drought; ecophysiological biomarkers; Instrumentation and Detectors; Leaves; Magnetic fields; Magnetic resonance imaging; Materials Science; Measurement methods; Measuring instruments; Medical Physics; Miniaturization; Moisture content; Multiscale analysis; NMR; NMR relaxation and imaging; Nuclear magnetic resonance; Overheating; Photosynthesis; Physics; Portable equipment; portable NMR setup; radio frequency clipping coil; Soil water; Sorghum; Spatial distribution; Time dependence; radio frequency clipping coil; portable NMR setup; abiotic stresses in plant; ecophysiological biomarkers; NMR relaxation and imaging
• ISSN: 0749-1581; 1097-458X
• DOI: 10.1002/mrc.4905

Today, in the presence of global warming, understanding how plants respond to drought stress is essential to meet the challenge of developing new cultivars and new irrigation strategies, consistent with the maintenance of crop productivity. In this context, the study of the relation between plants and water is of central interest for modeling their responses to biotic and abiotic constraints. Paradoxically, there are very few direct and noninvasive methods to quantify and measure the level and the flow of water in plants. The present work aims to develop a noninvasive methodology for living plant based on nuclear magnetic resonance (NMR) at low magnetic field and imaging (MRI) to tackle the issue of water quantity in plants. For this purpose, a portable NMR device measuring the signal level at 8 mT was built. This instrument addresses specific challenges such as miniaturization, accessibility, and overheating in order to maintain the plant intact of time over long period. Time dependence of the water content in sorghum plants is reported under abiotic stress as well as the fraction of transpirable soil water and the photosynthesis activity through the leaves. At high magnetic field (9.4 T), T2 maps were acquired on the same sorghum plants at two time points. The combination of these approaches allows us to identify ecophysiological biomarkers of drought stress. One particular interesting result concerns the spatial distribution of water in two anatomically contrasted sorghum genotypes. We present a noninvasive investigation of drought stress in sorghum plants. NMR signals from a homemade portable system, fraction of transpirable soil water (FTSW), photosynthesis activity, and high‐resolution images from MRI scanner over 2 weeks reveal the time dependence of water content and anatomy differences in watered versus stressed conditions. These approaches allow to clearly discriminate the resistant sorghum genotypes and to identify some markers of drought stress tolerance.