Effect of iron deficiency on the chemical composition of the xylem sap of barley

Abstract
Barley (Hordeum vulgare L.) plants were grown hydroponically, and the effect of Fe deficiency on the concentration of essential metals, phytosiderophores (PS), organic acids, and amino acids, in the xylem sap was elucidated. The Fe-deficient plants exuded xylem sap at a rate about 2A-fold lower than the Fe-sufficient plants. Under Fe deficiency, the concentration of Fe decreased compared with that of Fe-sufficient plants, while the concentrations of K, Ca, and Mg were not significantly different, and those of Mn, Zn, and Cu increased by Fe deficiency. The concentration of PS in the xylem sap of the Fe-deficient plants was about 24-fold higher than that of the Fe-sufficient plants. The concentrations of citrate, malate, and succinate in the xylem sap increased 7.3-fold, 2.0-fold, and 1.8-fold, respectively, with Fe deficiency compared to those of the Fe-sufficient plants. The xylem concentration of total amino acids increased 1.4-fold by Fe deficiency.