c6.6.11 – Distribution and concentration of Cd in root tissue of Populus alba by scanning electron microscopy and energy-dispersive X-ray microanalysis

Cocozza C (1), Tognetti R (1), Minnocci A (2), Iori V (3), Zacchini M (3), Scarascia Mugnozza G (3)

(1) EcoGeoFor Lab – Dipartimento STAT, Università degli Studi del Molise, I-86090 Pesche, Italy; (2) BioLabs, Scuola Superiore Sant’Anna, I-56025 Pontedera, Italy; (3) IBAF-CNR, I-00016 Monterotondo Scalo.
Collocazione: c6.6.11 – Tipo Comunicazione: Presentazione orale
6° Congresso SISEF *
Sessione 6: “Poster: “Fattori di stress e strategie di mitigazione”” *

Contatto: Tognetti Roberto (tognetti@unimol.it)

Abstract: In a polluted environment with potentially toxic elements, plants may play a relevant role on contaminant absorption or stabilization. The aim of this study was to discriminate two poplar clones in their tolerance to high Cd concentrations in the growth solution and to show the potential of poplar in the cleaning-up of Cd-contaminated substrate. Chemical analyses to determine the content of heavy metals in biological samples involve their destruction by digestion with concentrated acids, preventing the localization of potentially toxic elements in situ. In contrast, scanning electron microscopy equipped with energy-dispersive x-ray microanalysis may provide information on element localization and chemical composition of biological samples at tissue and cell levels. Scanning electron microscopy allows for observation of samples in their native state (dry or wet) with high magnifications with a minimum sample preparation, good field depth observations inside of the sample, and possibility to combine with energy-dispersive x-ray microanalysis obtaining digital images. Although, energy-dispersive x-ray microanalysis has relatively low detection limits, it is useful in establishing distribution maps of potentially toxic elements since performing punctual chemical analysis. Tissue localization and concentration of Cd (and other elements) in root tips of Populus alba clones (6K3 and 14P11) were investigated, using energy-dispersive x-ray microanalysis coupled both to a digital scanning electron microscope and to a low-temperature scanning electron microscope. These techniques were useful to identify in situ distribution and concentration of Cd in poplar roots, establishing indirect correlations between accumulation and localization of the metal. Overall, observations suggested differential patterns between 6K3 and 14P11 clones in accumulating Cd within the root profile, though overall concentration and content of Cd in the root system, determined by atomic absorption spectrophotometry, did not differ between clones. The possibility that these accumulation patterns arise from differences in uptake processes and structural properties is discussed and related to tolerance mechanisms.

Citazione: Cocozza C , Tognetti R , Minnocci A , Iori V , Zacchini M , Scarascia Mugnozza G (2007). Distribution and concentration of Cd in root tissue of Populus alba by scanning electron microscopy and energy-dispersive X-ray microanalysis . 6° Congresso Nazionale SISEF, Arezzo, 25 – 27 Set 2007, Contributo no. #c6.6.11