In the present study, using ultrasonic irradiations, a novel nano-sized iron complex has been prepared from aminolevulinic acid and iron(III) nitrate under greenhouse conditions. The obtained Fe nano-sized complex has been characterized by two methods of Fourier-transform infrared spectroscopy (FTIR) and EDX spectra (Energy-dispersive X-ray spectroscopy). Also, the morphology and size of the nano-complex were determined using transmission electron microscopy (TEM) and it showed an acceptable size in the nano range (5–20 nm). In this work, purslane plants were supplied with Fe(III)–aminolevulinic acid (Fe-ALA) as a new nano-sized complex and Fe-EDDHA [Fe-ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid)]. The mineral nutrients concentrations, total phenolic, ascorbic acid contents and antioxidant activity were the highest in plants treated with Fe-ALA nano-complex. Catechin was the predominant phenolic compound in all treated plants. Fe nano-complex at the rate of 0.2% induced extra high phenolic compounds value. Shoot Fe, Zn, N, Mg, Ca and K contents were also higher in Fe nano-complex treated plants than the control and in plants that were treated by Fe-EDDHA. Overall, the nutritional and pharmaceutical quality of Portulaca oleracea improved the use of the nano-sized Fe-ALA complex as a new iron source.

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