Adaptive response of Vitis spp. and Prunus spp. to Fe-deficiency induced by HCO3-

Iron chlorosis is a nutritional disorder often linked to an excess of calcium carbonate in the soil which induces iron deficiency by increasing the pH of the bulk soil solution. Plants metabolism is strongly compromised with negative repercussions both on the production and on the quality. Strategy I plants, including grape and peach, respond to this problem by inducing morphological and physiological modifications as development of lateral roots, differentiation of specialized transfer cells, increase in a plasma membrane-bound reductase, acidification of the rhizosphere, release of phenolics and increase in the organic acids synthesis. The aim of this work was to study the role of HCO3- at root level and in the upper part of the plant. Own rooted cuttings of Vitis vinifera cv Cabernet Sauvignon (very resistant to iron chlorosis) and of Vitis riparia cv Martineau (susceptible to iron chlorosis) were grown in hydroponic culture with different concentrations of HCO3- and without iron. Concerning peach, eight different rootstocks with different tolerance to iron chlorosis were grown in pots containing calcareous and standard soils. For both species, roots and leaf tissues were assayed for acidification and reductase capacities and malic and citric acid content; total chlorophyll and total Fe content were determined, and starch content in peach roots was measured. Differences emerged in root and leaf tissues of plants grown in the presence and absence of HCO3-, in response to experimental conditions, confirming the literature.