COMPARISON BETWEEN NANO IRON AND IRON EDTA AS FOLIAR FERTILIZERS UNDER SALT STRESS CONDITIONS

A greenhouse experiment was adopted to investigate the effect of nano Fe on the growth, nutrients concentration, and content of sorghum straw, racemes and whole shoots in comparison to Fe-EDTA under salt stress conditions. Two sources of iron fertilizers; nano Fe 1.35 g/L, Fe-EDTA 3 g/L were sprayed and distilled water was used as a control. Sorghum plants were irrigated by diluted seawater in rates of 2.5, 5% seawater, and tap water as a control. Transmission electron microscope (TEM) results illustrated that the shape of used nano Fe was spherical with an average particle size of 47.67nm. Only the high salinity level reduced the growth attributes. As an unexpected result, the growth parameters recorded in iron-EDTA treatments were superior to those obtained from the nano-iron source, irrespective of the salinity level. The foliar application of iron EDTA increased the plant height, the fresh weight (fw) of straw, fw of raceme, fw of whole plant, the dry weight (dw) of stem, dw of straw, dw of raceme and dw of whole shoot by 24.0, 57.6, 22.5, 53.1, 62.2, 39.0, 16.4 and 34.0% compared with nano-Fe, respectively. We attributed this result to the defensive response of the plant towards the nano-iron as indicated by appearance of four petals flower-like silicon units in SEM micrographs of nano Fe-sprayed leaves.