Effect of Iron Deficiency on Gas Exchange and Catalase and Peroxidase Activity in Citrus

Abstract

Abstract The effects of iron (Fe) deficiency on catalase and peroxidase activity, net photosynthesis (Pn), stomatal conductance (g s ), plant water relations, and specific leaf weight, were studied under greenhouse conditions in two sweet orange (C. sinensis) cultivars grafted on sour orange (Citrus aurantium) and Swingle citrumelo (C. paradisi × P. trifoliata). Iron deficiency caused by the absence of Fe in the Hoagland nutrient solution reduced significantly catalase and peroxidase activity, photosynthesis (Pn), osmotic potential (Ψ π ), turgor potential (Ψ p ), and specific leaf weight, but did not influence g s and leaf water potential (Ψ L ). Iron deficiency caused by increasing concentrations of bicarbonate supplied as NaHCO3 (10 and 40 mM) in the nutrient solution reduced significantly g s , Pn, and Ψ p and increased Ψ L and Ψ π . Furthermore, remarkable differences were recorded between the various cultivars/rootstocks combinations.