Water mobility in the endosperm of high beta-glucan barley mutants as studied by nuclear magnetic resonance imaging

Biomechanical properties of wheat grains: the implications on milling

Millennia of continuous innovation have driven ever increasing efficiency in the milling process. Mechanically characterizing wheat grains and discerning the structure and function of the wheat bran layers can contribute to continuing innovation. We present novel shear force and puncture force testing regimes to characterize different wheat grain cultivars. The forces endured by wheat grains during the milling process can be quantified, enabling us to measure the impact of commonly applied grain pretreatments, such as microwave heating, extended tempering, enzyme and hormone treatments on grains of different ‘hardness’. Using these methods, we demonstrate the importance of short tempering phases prior to milling and identify ways in which our methods can detect differences in the maximum force, energy and breaking behaviours of hard and soft grain types. We also demonstrate for the first time, endosperm weakening in wheat, through hormone stratification on single bran layers. The modern milling process is highly refined, meaning that small, cultivar specific, adjustments can result in large increases in downstream profits. We believe that methods such as these, which enable rapid testing of milling pretreatments and material properties can help to drive an innovation process that has been core to our industrial efforts since prehistory.

Can β-D-Glucan Protect Oat Seeds against a Heat Stress?

Plants have evolved to live in environments where they are often exposed to different stress factors. Being sessile, they have developed specific mechanisms that allow them to detect precisely environmental changes and respond to complex conditions, minimizing damage while conserving valuable resources for growth and reproduction. The cell wall polysaccharide β-D-glucan observed in some species of Poales can determine responses to various environmental factors in specific plant developmental stages. It is located in the outer epidermal layer, at the place of stress attack and therefore its metabolism could relate to response of plant to environmental factors within moderate, physiological range. Putative protective role of β-D-glucan during heat stress was indicated through naked oats with higher content of β-D-glucan. It appeared that oats with higher β-D-glucan content are better adapted to stress conditions. The presented article discusses the β-D-glucan as a possible protective mechanism in oat during (heat) stress conditions.

Surveying the plant's world by magnetic resonance imaging

Understanding the way in which plants develop, grow and interact with their environment requires tools capable of a high degree of both spatial and temporal resolution. Magnetic resonance imaging (MRI), a technique which is able to visualize internal structures and metabolites, has the great virtue that it is non-invasive and therefore has the potential to monitor physiological processes occurring in vivo. The major aim of this review is to attract plant biologists to MRI by explaining its advantages and wide range of possible applications for solving outstanding issues in plant science. We discuss the challenges and opportunities of MRI in the study of plant physiology and development, plant-environment interactions, biodiversity, gene functions and metabolism. Overall, it is our view that the potential benefit of harnessing MRI for plant research purposes is hard to overrate.

In vivo ¹H-NMR microimaging during seed imbibition, germination, and early growth

Magnetic resonance imaging (MRI) is a superior noninvasive diagnostic tool widely used in clinical medicine, with more than 60 million MRI tests performed each year worldwide. More specialized high-resolution MRI systems capable of a resolution that is 100-1,000 times higher than standard MRI instruments are used primarily in materials science, but are used with increasing frequency in plant physiology. We have shown that high-resolution (1)H-nuclear magnetic resonance (NMR) microimaging can provide a wealth of information about the internal anatomy of plant seeds as small as 1 mm or even smaller. This chapter covers the methods associated with these imaging techniques in detail. We also discuss the application of (1)H-NMR microimaging to study in vivo seed imbibition, germination, and early seedling growth.

Changes in water content and distribution in Quercus ilex leaves during progressive drought assessed by in vivo 1H magnetic resonance imaging

BACKGROUND

Drought is a common stressor in many regions of the world and current climatic global circulation models predict further increases in warming and drought in the coming decades in several of these regions, such as the Mediterranean basin. The changes in leaf water content, distribution and dynamics in plant tissues under different soil water availabilities are not well known. In order to fill this gap, in the present report we describe our study withholding the irrigation of the seedlings of Quercus ilex, the dominant tree species in the evergreen forests of many areas of the Mediterranean Basin. We have monitored the gradual changes in water content in the different leaf areas, in vivo and non-invasively, by 1H magnetic resonance imaging (MRI) using proton density weighted (rhow) images and spin-spin relaxation time (T2) maps.

RESULTS

Rhow images showed that the distal leaf area lost water faster than the basal area and that after four weeks of similar losses, the water reduction was greater in leaf veins than in leaf parenchyma areas and also in distal than in basal leaf area. There was a similar tendency in all different areas and tissues, of increasing T2 values during the drought period. This indicates an increase in the dynamics of free water, suggesting a decrease of cell membranes permeability.

CONCLUSIONS

The results indicate a non homogeneous leaf response to stress with a differentiated capacity to mobilize water between its different parts and tissues. This study shows that the MRI technique can be a useful tool to follow non-intrusively the in vivo water content changes in the different parts of the leaves during drought stress. It opens up new possibilities to better characterize the associated physiological changes and provides important information about the different responses of the different leaf areas what should be taken into account when conducting physiological and metabolic drought stress studies in different parts of the leaves during drought stress.