ADAPTIVE RESPONSES TO HIGH CONCENTRATION OF HCO₃^- IN ‘CABERNET SAUVIGNON’

Lime-induced chlorosis is a problem of absorption and metabolism of iron (Fe) caused by an excess of calcium carbonate in the soil. Strategy I plants, including grape, respond to Fe-deficiency by inducing physiological and biochemical modifications in order to increase Fe uptake. Concerning the role of HCO₃^-, there is evidence about its influence at the root level, but it is not clear if it affects some processes in the upper part of the plant, particularly in the leaves. In this work, own rooted cuttings of Cabernet Sauvignon (very resistant to lime-induced chlorosis) were grown in hydroculture with different concentrations of HCO₃^- and in absence of Fe³⁺ -EDTA. It was found that this cultivar retains the capacity to respond to adverse conditions by activating some mechanisms expected of Strategy I plants when increasing concentrations of HCO₃^- are administered, similar to those which occurred under Fe-deficiency. In particular, in the presence of bicarbonate, reductase activity increased both in roots and leaves while total chlorophyll and Fe content in the leaves showed a decreasing trend.