INVESTIGATIONS ON IRON UPTAKE AND REDUCTION BY EXCISED ROOTS OF DIFFERENT GRAPEVINE ROOTSTOCKS AND A V-VINIFERA CULTIVAR

Roots from cuttings of grapevine rootstocks V. Berlandieri x V. rupestris 140 Ru, V. Berlandieri x V. riparia SO4, V. riparia x V. rupestris 101-14 and a V. vinifera cultivar (Pinot blanc), with a decreasing degree of chlorosis resistance, were excised and tested to quantify physiological and morphological parameters, as follows: Fe-59 uptake from an FeEDTA solution; reducing capacity; root diameter and root hair occurrence. The most significant findings are that: a) Fe-59 uptake and FeEDTA reduction decreased from the most chlorosis resistant rootstock ('140 Ru') to the most susceptible one ('101-14') and to Pinot blanc; b) Fe-59 uptake and reducing capacity were closely related; c) iron uptake and reduction were closely related to the root diameter and root hair occurrence, within the rootstocks.