title: X-ray imaging of leaf venation networks.
abstract: Leaf venation networks mediate many plant resource fluxes and are therefore of broad interest to research questions in plant physiology, systematics, paleoecology, and physics. However, the study of these networks is limited by slow and destructive imaging methods. X-ray imaging of leaf veins is potentially rapid, of high resolution, and nondestructive. Here, we have developed theory for absorption- and phase-contrast X-ray imaging. We then experimentally test these approaches using a synchrotron light source and two commercially available X-ray instruments. Using synchrotron light, we found that major veins could be consistently visualized using absorption-contrast imaging with X-ray energies < 10 keV, while both major and minor veins could be consistently visualized with the use of an iodine contrast agent at an X-ray energy of 33.269 keV. Phase-contrast imaging at a range of energies provided high resolution but highlighted individual cell walls more than veins. Both approaches allowed several hundred samples to be processed per d. Commercial X-ray instruments were able to resolve major veins and some minor veins using absorption contrast. These results show that both commercial and synchrotron X-ray imaging can be successfully applied to leaf venation networks, facilitating research in multiple fields.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E Lowell St, Tucson, AZ, 85721, USA.|Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, CO, 81224, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Blonder
authors.affiliation: Argonne National Laboratory, Advanced Photon Source, 9700 South Cass Avenue, Lemont, IL, 60439, USA.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Carlo
authors.affiliation: Center for Gamma-Ray Imaging, Department of Radiology, University of Arizona, PO Box 245067, Tucson, AZ, 85724, USA.
authors.forename: Jared
authors.initials: J
authors.lastname: Moore
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago, 9700 South Cass Avenue, Lemont, IL, 60439, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Rivers
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E Lowell St, Tucson, AZ, 85721, USA.|Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, CO, 81224, USA.|Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, 87501, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Enquist
mesh_terms: D019659:Asteraceae / Q000033:anatomy & histology; D003287:Contrast Media; D007455:Iodine; D018515:Plant Leaves / Q000033:anatomy & histology*; D017356:Synchrotrons; D014057:Tomography, X-Ray Computed / Q000379:methods; D056928:X-Ray Absorption Spectroscopy / Q000379:methods*
chemical_list: D003287:Contrast Media; D007455:Iodine