Influence of Divalent and Trivalent Sources of Iron on Growth, Iron Uptake-Transport and Photosynthetic Pigments in Rice (Oryza sativa L.) Cultivars During the Vegetative Stage

Abstract

Rice (Oryza sativa L.) is the most significant staple food globally. It can cultivate in a wide range of environments. Iron (Fe) deficiency is an important abiotic stress in crop production. To deal with Fe deficiency, plants have evolved mechanisms for Fe uptake. The study aims to examine the abilities of the cultivars - Biga & Idot;ncisi, Osmanc & imath;k-97, Hamzadere, Ronaldo, and Edirne - to utilize both non-chelated (FeSO4<middle dot>7 H2O) and chelated forms (Fe(II)-EDTA and Fe(III)-EDTA) of Fe, which exist in divalent and trivalent states, along with their physiological responses to these different forms of Fe. All cultivars were grown in a sand culture under Fe-deficient (Fe:0) and -sufficient conditions (45 mu M Fe). Roots of all rice cultivars grown under Fe deficiency conditions exhibited both phytosiderophore (PS) release and ferric chelate reductase (FCR) activity. These results indicate that all cultivars can employ a Combined Strategy (Strategy I/II) mechanism for Fe uptake. Nevertheless, the efficiency of rice plants in utilizing Strategy I and Strategy II mechanisms for Fe uptake varied depending on the cultivars. Hamzadere exhibited higher PS production, whereas Ronaldo displayed higher FCR activity. The application of divalent and trivalent Fe sources significantly increased the dry weight of shoots, Fe uptake by shoots and roots, and the pigment content of leaves in the rice cultivars. For other cultivars except Hamzadere and Edirne, the utilization rate of Fe(II)-EDTA was higher than that of Fe(III)-EDTA and FeSO4.7 H2O. The cultivar Osmanc & imath;k-97 had the highest utilization rate (21.30%) of Fe(II)-EDTA.