Flavonoids and low molecular weight organic acids are some of the most representative classes of organic molecules contained in root exudates. While the role of organic acids as effective complexants is quite clearly established, the processes involving flavonoids in elemental mobilization are far from being fully understood. In this research we studied the interactions of various low molecular weight organic acids (citric, oxalic and malic acids) and flavonoids (quercetin, rutin, and genistein) with two different agricultural soils, one acidic and one alkaline. In addition, synergistic and competitive effects were assessed for the mobilization of Al, Si, Fe, Cu, Zn, Mn, Cd, Cr, Ni and Pb by using different combinations of the above-cited compounds. Mobilization processes strongly depended on the soil type and the nature of the element which is being mobilized. More specifically, citrate out of the three organic acids was the most effective in acid soil while oxalate was able to extract more Cu, Zn and Ni in alkaline soil. Furthermore, in acid soil synergistic effect by organic acids was observed only for Mn. In alkaline soil it was noticed for Si, while for Al, Cu, Zn and Ni a competitive effect occurred. While organic acids may be mainly involved in complexation reactions promoting the desorption of elements from soil minerals, flavonoids appear to promote redox reactions which enhance significantly the solubilization of Fe and Mn. In particular, rutin is much more effective than citrate for Fe mobilization in alkaline soil while quercetin and rutin in combination with citrate can desorb as much as five times the amount of Mn which is extracted by citrate alone. The effects of flavonoids and organic acids on soil mineralogy are also being evaluated by XRD (X-Ray Diffraction) and SEM-EDX (Scanning Electron Microscopy coupled to Energy Dispersive X-ray spectroscopy).
Combined Effect of Flavonoids and Organic Acids on the Mobilization of Major and Trace Elements in Soil
L Medici;
2013
Abstract
Flavonoids and low molecular weight organic acids are some of the most representative classes of organic molecules contained in root exudates. While the role of organic acids as effective complexants is quite clearly established, the processes involving flavonoids in elemental mobilization are far from being fully understood. In this research we studied the interactions of various low molecular weight organic acids (citric, oxalic and malic acids) and flavonoids (quercetin, rutin, and genistein) with two different agricultural soils, one acidic and one alkaline. In addition, synergistic and competitive effects were assessed for the mobilization of Al, Si, Fe, Cu, Zn, Mn, Cd, Cr, Ni and Pb by using different combinations of the above-cited compounds. Mobilization processes strongly depended on the soil type and the nature of the element which is being mobilized. More specifically, citrate out of the three organic acids was the most effective in acid soil while oxalate was able to extract more Cu, Zn and Ni in alkaline soil. Furthermore, in acid soil synergistic effect by organic acids was observed only for Mn. In alkaline soil it was noticed for Si, while for Al, Cu, Zn and Ni a competitive effect occurred. While organic acids may be mainly involved in complexation reactions promoting the desorption of elements from soil minerals, flavonoids appear to promote redox reactions which enhance significantly the solubilization of Fe and Mn. In particular, rutin is much more effective than citrate for Fe mobilization in alkaline soil while quercetin and rutin in combination with citrate can desorb as much as five times the amount of Mn which is extracted by citrate alone. The effects of flavonoids and organic acids on soil mineralogy are also being evaluated by XRD (X-Ray Diffraction) and SEM-EDX (Scanning Electron Microscopy coupled to Energy Dispersive X-ray spectroscopy).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
