Mapping the intake of different elements in vegetal tissues by dual‐energy X‐ray imaging at DaΦne synchrotron light source

Abstract

This article reports on the first utilization of the soft X-ray beamline at the DaPhine synchrotron light source for mapping the intake of different elements in plant tissues. As a test, the method of dual-energy X-ray microradiography was applied to the investigation of the natural sulfur content in dried leaf and root samples. Our ultimate goal was to monitor the pollutant lead and its intake, which was added in controlled doses to the hydroponic medium of laboratory-controlled samples of vegetal species. The results obtained by the nondestructive X-ray radiographic analysis are compared to the values of concentrations determined by a standard chemical analysis utilizing atomic absorption spectroscopy. From this comparison the validity of the X-ray detection of heavy metals in biological samples has been confirmed. The superposition of the dual energy results on the simple planar radiography shows the representation of the pollutant intake directly on the sample structures. It should be pointed out that this method, developed here for plant root and leaves could be applied to any biological sample of interest, but the preparation and observation conditions necessitate different strategies according to the type of sample under analysis.

Detection of lead in Zea mays by dual‐energy X‐ray microtomography at the SYRMEP beamline of the ELETTRA synchrotron and by atomic absorption spectroscopy

“…Moreover, the vermiculite, being a mineral characterized by a high capacity as a cationic exchanger, strongly interacts with the ions present in the solution, binding them on its surface (Malandrino et al, 2006). For these reasons, using the AAS apparatus, the concentration of the biodisposable lead (Reale et al, 2008) has been directly measured in the prepared solutions (control, 0.1, 1.0, 10 mM) used for the plants observed by the dual-energy method (Hoagland's solution with different lead acetate concentrations) together with the vermiculite substrate in the same experimental conditions used for growing plants, and also in their absence. The measured values of the biodisposable lead are shown in Table 3.…”

“…Even the remediation techniques could be more properly applied if the effective degree of remediation could be quickly and precisely evaluated (Kaiser et al, 2004(Kaiser et al, , 2005(Kaiser et al, , 2007Reale et al, 2008).…”

“…A detailed account of the dual-energy algorithm and its implementation for elemental mapping were given in our earlier articles (Kaiser et al, 2005(Kaiser et al, , 2007Reale et al, 2008). In those experiments, dual-energy X-ray microradiography were tested on different plant samples grown in laboratory conditions with contaminants (e.g., Pb, Cd, Cu) added in controlled doses.…”

“…Moreover, synchrotron radiation can be tuned at the desired wavelength, and because of its high intensity, it is also able to detect very low amount of contaminants. Different techniques can be applied using X-rays from synchrotron sources: dual-energy (i.e., imaging of samples at X-ray energy above and below the edge of the heavy elements under study) radiography and tomography (Kaiser et al, 2005(Kaiser et al, , 2007Reale et al, 2008), projection microscopy with zone plate lenses (Yada 2009;Awaji et al, 2001), diffraction microscopy (Shapiro et al, 2005), X-ray scanning transmission microscopy (Hornberger et al, 2007), as well as X-ray microfluorescence.…”