Investigations on some physiological parameters involved in chlorosis occurrence in grafted grapevine

Abstract

V. vinifera L. cv. Chardonnay was grafted on three hybrid rootstocks inducing a decreasing degree of chlorosis resistance, as follows: V. Berlandieri x V. rupestris 140 Ru (iron‐efficient), V. Berlandieri x V. riparia S.O.4 (iron‐efficient), V. riparia x V. rupestris 101–14 (iron‐inefficient). The grafted vines were grown in pots of a calcareous and a noncalcareous soil. Leaves selected at the middle and end of the annual growing period were assayed for a, b, and total chlorophyll, ferrous iron, macronutrients, and trace elements. The most significant findings are: a) the total chlorophyll and the ferrous iron of the vines growing on calcareous soil, are higher in the plants grafted on the chlorosis resistant rootstocks (140 Ru and S.O.4) compared to those grafted on the chlorosis susceptible one (101–14); b) increasing chlorosis symptoms are related to a low iron translocation to the leaves; c) increasing chlorophyll levels are related to decreasing K/Ca and P/Fe leaf ratios.