Fe deficiency induction in Poncirus trifoliata rootstock growing in nutrient solution changes its performance after transplant to soil

tThe absence of iron (Fe) in the nutrient solution induces several physiological and morphological adapta-tions in the roots of Poncirus trifoliata, a citrus rootstock, thereby modifying its overall nutritional status.Whether these changes are advantageous when plants are transplanted to calcareous soils needs to beassessed. To achieve this objective a two-phase experiment was established, first in nutrient solution(phase I) then in pots containing different soils (phase II). In phase I, P. trifoliata L. Raf. plants were grownin Hoagland’s solution with 120 M of Fe (Fe120 treatment) or without (Fe0 treatment). At the end ofphase I (87 days), Fe-chlorotic plants had less chlorophyll in apical younger leaves, root tips were swollenand their FC-R activity was enhanced, typical responses to Fe-stress. Chlorotic plants had less Fe com-pared to control plants, but accumulated more Cu and Zn. In contrast the root to shoot ratio (dry weight)and the amounts of macronutrients were not affected by Fe chlorosis. In phase II, plants of both treat-ments were transplanted to pots containing a calcareous (C) or a non-calcareous (nC) soil resulting in fourtreatments: Fe0nC, Fe120nC, Fe0C and Fe120C. From the end of phase I until the end of the experiment(353 days), the calcareous soil negatively affected the overall nutritional balance in both Fe0 and Fe120treatments. Apparently, the ability to change metal homeostasis in particular Cu, as a Fe-stress responsewas maintained in plants grown in non-calcareous soil. Moreover, the previous induction of physiologi-cal and morphological adaptations to Fe depletion alleviated the iron chlorosis symptoms caused by soilcarbonates. These results may point to the utilization of internal stress signalling as a tool to cope withdifferent soil conditions