Fe-deficiency response in Parietaria diffusa : a calcicole plant

Pellitory of the wall (Parietaria diffusa L.), a dicotyledonous wild plant belonging to the family of Urticaceae, is widespread on calcareous soils, and also on walls and debris, were lime concentration, sometimes, is extremely high; it may then be considered a calcicole plant. Since high pH values and the presence of CaCO3 and HCO3- cause low Fe solubility, its availability in such substrates could be the ecological factor limiting the distribution of spontaneous plants in calcareous soils, and a calcareous soil-born plant should be characterized by a higher Fe-efficiency in comparison with calcifuge ones. Parietaria diffusa was grown in nutrient solutions in the presence and in the absence of Fe, and in the presence of CaCO3 and bicarbonate at two concentrations (5 and 15mM), in order to simulate a natural substrate with different lime contents. Some biochemical parameters were determined and the morphological and hystological modifications of the root system were evaluated in order to verify whether Parietaria is a Fe-efficient plant and adopts the adaptive mechanisms of Strategy I Fe-efficient plants.