Circulation of water within wheat grain revealed by nuclear magnetic resonance micro-imaging

Jenner, CF; Xia, Yafeng; Eccles, C.D.; Callaghan, Paul T.

doi:10.1038/336399a0

Cited by 118 publications

(54 citation statements)

References 7 publications

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“…Here, light-induced changes in T2 were shown to occur within the crease region (Fig. 2B), which is the primary entry point into the grain for not only solutes , but also water (Jenner et al, 1988). Given this, it becomes reasonable to suggest that the response The data correspond to the analysis of three biological 3 $ three technical repetitions; *, Student's t test significance at P , 0.05; **, Student's t test significance at P , 0.01; and ***, Student's t test significance at P , 0.001.…”

Section: The Ear and Caryopsis Respond To Illumination By Adjusting Tmentioning

confidence: 99%

Metabolic architecture of the cereal grain and its relevance to maximize carbon use efficiency

et al. 2015

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Here, we have characterized the spatial heterogeneity of the cereal grain's metabolism and demonstrated how, by integrating a distinct set of metabolic strategies, the grain has evolved to become an almost perfect entity for carbon storage. In vivo imaging revealed light-induced cycles in assimilate supply toward the ear/grain of barley (Hordeum vulgare) and wheat (Triticum aestivum). In silico modeling predicted that, in the two grain storage organs (the endosperm and embryo), the light-induced shift in solute influx does cause adjustment in metabolic flux without changes in pathway utilization patterns. The enveloping, leaf-like pericarp, in contrast, shows major shifts in flux distribution (starch metabolism, photosynthesis, remobilization, and tricarboxylic acid cycle activity) allow to refix 79% of the CO 2 released by the endosperm and embryo, allowing the grain to achieve an extraordinary high carbon conversion efficiency of 95%. Shading experiments demonstrated that ears are autonomously able to raise the influx of solutes in response to light, but with little effect on the steady-state levels of metabolites or transcripts or on the pattern of sugar distribution within the grain. The finding suggests the presence of a mechanism(s) able to ensure metabolic homeostasis in the face of short-term environmental fluctuation. The proposed multicomponent modeling approach is informative for predicting the metabolic effects of either an altered level of incident light or a momentary change in the supply of sucrose. It is therefore of potential value for assessing the impact of either breeding and/or biotechnological interventions aimed at increasing grain yield.Raising the productivity of a given crop genotype requires an increase in the plant's ability to efficiently respond to a changeable environment. At the physiological level, this involves adjustments to the photosynthetic activity of its leaves, to the control of assimilate movement from source to sink, and to the efficiency of assimilate storage. The manipulation of the plant's efficiency to fix carbon, to use energy and nutrients, and to utilize water has been suggested as a route for improving crop productivity (Amthor 2010;De Block and Van Lijsebettens, 2011). Particular attention has been devoted to the cereals, given their central role in the human diet. While the necessary integration of physiological and developmental processes in all plants relies on the transmission of hormonal, metabolic, and other signals through the vascular system (van Bel et al., 2013), this is not the case in the cereal grain, because this network does not extend beyond the pericarp, a maternal structure that encloses the filial storage organs (embryo and endosperm; Radchuk and Borisjuk, 2014). The isolation of the filial from the maternal tissues in the cereal grain creates a complex metabolic system, involving, at the least, a tripartite interaction between the pericarp, endosperm, and embryo. These three grain components in effect form an interactive system of autonomous...

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Section: The Ear and Caryopsis Respond To Illumination By Adjusting Tmentioning

confidence: 99%

Metabolic architecture of the cereal grain and its relevance to maximize carbon use efficiency

et al. 2015

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“…glass capillary and, in order to avoid movement during the experiment, pressed slightly against each other with a piece of matching Teflon tube at each end of the glass tube. This capillary was then positioned inside the superconducting magnet (Jenner et al, 1988;Fountain et al, 1998;Manz et al, 2003;Schneider et al, 2003). There is no external movement of the sample tube, e.g.…”

Section: Mas Nmr Spectroscopy and Mrmmentioning

confidence: 99%

“…0.1 mm), this method of imaging may be termed microscopic (Callaghan, 1991). MRI and 1 H-NMR microimaging (MRM) have been used to study water uptake and flow in relatively large seeds of legumes (Pouliquen et al, 1997;Fountain et al, 1998), trees (Carrier et al, 1999;Roh et al, 2004;Terskikh et al, 2005), and of cereal grains (Jenner et al, 1988;Chudek and Hunter, 1997;Hou et al, 1997;Gruwel et al, 2002;Kö ckenberger et al, 2004;Krishnan et al, 2004). Redistribution of water and tissue-specific differences in moisture content were detected in these seeds.…”

mentioning

confidence: 99%

Water Uptake and Distribution in Germinating Tobacco Seeds Investigated in Vivo by Nuclear Magnetic Resonance Imaging

et al. 2005

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The regulation of water uptake of germinating tobacco (Nicotiana tabacum) seeds was studied spatially and temporally by in vivo 1 H-nuclear magnetic resonance (NMR) microimaging and 1 H-magic angle spinning NMR spectroscopy. These nondestructive state-of-the-art methods showed that water distribution in the water uptake phases II and III is inhomogeneous. The micropylar seed end is the major entry point of water. The micropylar endosperm and the radicle show the highest hydration. Germination of tobacco follows a distinct pattern of events: rupture of the testa is followed by rupture of the endosperm. Abscisic acid (ABA) specifically inhibits endosperm rupture and phase III water uptake, but does not alter the spatial and temporal pattern of phase I and II water uptake. Testa rupture was associated with an increase in water uptake due to initial embryo elongation, which was not inhibited by ABA. Overexpression of b-1,3-glucanase in the seed-covering layers of transgenic tobacco seeds did not alter the moisture sorption isotherms or the spatial pattern of water uptake during imbibition, but partially reverted the ABA inhibition of phase III water uptake and of endosperm rupture. In vivo 13 C-magic angle spinning NMR spectroscopy showed that seed oil mobilization is not inhibited by ABA. ABA therefore does not inhibit germination by preventing oil mobilization or by decreasing the water-holding capacity of the micropylar endosperm and the radicle. Our results support the proposal that different seed tissues and organs hydrate at different extents and that the micropylar endosperm region of tobacco acts as a water reservoir for the embryo.

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“…Finally, studies with tritiated water have shown that extremely little fluid is cycled back out ofjuice sacs (T-B Huang, KE Koch, unpublished data). Tissue expansion may thus be vital to nonvascular transfer in such a system, both for release of turgor (allowing mass flow and/or effective sugar compartmentalization [12,33] [15]), or between epidermis and underlying parenchyma (as indicated for rice nucellus [26]), or possibly between endoplasmic reticulum and the cytoplasmic anulus ofplasmodesmata (10), or even between night and day (with diumal oscillations in waterflow [17]). Extremely little water appears to leave juice sacs, however (17, …”

Section: Water Movementmentioning

confidence: 99%

Postphloem, Nonvascular Transfer in Citrus

Koch¹,

Avigne²

1990

Plant Physiol.

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Circulation of water within wheat grain revealed by nuclear magnetic resonance micro-imaging

Cited by 118 publications

References 7 publications

Metabolic architecture of the cereal grain and its relevance to maximize carbon use efficiency

Metabolic architecture of the cereal grain and its relevance to maximize carbon use efficiency

Water Uptake and Distribution in Germinating Tobacco Seeds Investigated in Vivo by Nuclear Magnetic Resonance Imaging

Postphloem, Nonvascular Transfer in Citrus

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