Characterization of the tolerance to iron chlorosis in different peach rootstocks grown in nutrient solution

Abstract

The response mechanisms to Fe chlorosis have been widely studied in herbaceous plants and qualitative and quantitative differences have been found among species and among genotypes within the same species. Similar studies on woody plants are scarce. The objective of this work was to characterize specific response mechanisms in peach rootstocks with differing tolerances to Fe chlorosis in calcareous soils and to determine where acidification and reduction occur along the root system. Plants were grown individually, in growth chamber, in flasks with 700 mL of aerated nutrient solution with or without Fe. Without Fe, the peach Nemaguard was the most chlorotic, developed the least reducing capacity and mobilized less Fe and Mn from roots to young leaves compared to the other rootstocks. The pH decrease of the nutrient solution with Fe-deficiency was significant only in the plum rootstocks. Using an agar technique, both responses, reducing capacity and acidification, were located at the subapical zones of the roots, although no swollen root tips were apparent.