JXB Advance Access published online on June 26, 2007
Journal of Experimental Botany, doi:10.1093/jxb/erm116
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© 2007 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)
RESEARCH PAPER |
Non-destructive diffraction enhanced imaging of seeds
1Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, Canada S7N 0X2
2National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973, USA
3Department of Anatomy and Cell Biology, 107 Wiggins Road, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
4Department of Applied Microbiology and Food Science, 51 Campus Drive, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A8
To whom correspondence should be addressed. E-mail: martin.reaney{at}usask.ca
Techniques that make possible the non-destructive continuous observation of plant anatomy and developmental processes provide novel insights into these phenomena. Non-destructive imaging of seeds was demonstrated using the synchrotron-based X-ray imaging technique, diffraction enhanced imaging (DEI). The seed images obtained had good contrast and definition, allowing anatomical structures and physiological events to be observed. Structures such as hypocotyl–root axes, cotyledons, seed coats, air cavities, and embryo-less Brassica napus L. seeds were readily observed using DEI. Embryo axes, scutella, pericarp furrows, coleoptiles, and roots were observable over a time-course in individual germinating Triticum aestivum L. caryopses. Novel anatomical and physiological observations were also made that would have been difficult to make continuously using other techniques. The physical principles behind DEI make it a unique imaging technique. Contrast in DEI is the result of X-ray refraction at the density differences occurring at tissue boundaries, scatter caused by regions containing ordered molecules such as cellulose fibres, and attenuation. Sectioning of samples and the infusion of stains or other contrast agents are not necessary. Furthermore, as high-energy X-rays are used (30–40 keV), little X-ray absorption occurs, resulting in low levels of radiation damage. Consequently, studies of developmental processes may be performed on individuals. Individual germinating B. napus and T. aestivum seeds were imaged at several time points without incurring any apparent radiation damage. DEI offers a unique way of examining plant anatomy, development, and physiology, and provides images that are complementary to those obtained through other techniques.
Key words: Diffraction enhanced imaging, NMR imaging, seed anatomy, tissue density, X-ray attenuation and refraction, X-ray imaging
* Present address: Department of Plant Science, 51 Campus Drive, University of Saskatchewan, Saskatoon, SK, Canada S7N 5A8.
Received 1 February 2007; Revised 26 April 2007 Accepted 30 April 2007