The potential of coated iron nanoparticles for modulating of negative effects of salinity stress in Ajowan

Salinity stress is one of the abiotic stressors that threatening medicinal plant yield with adverse effects on the biochemical and morphological parameters. One strategy to manage salt stress is to use plant nutritional modifiers to lessen its harmful effects. In this study, the positive role of coated Fe-nanoparticles with chitosan (coated Fe-NPs) has been investigated in modulating the negative effects of salinity stress on the growth and the biochemical responses of Ajowan (Trachyspermum ammi L.) plants. In the treated plants with coated Fe-NPs (5, 10, and 15 μM L⁻¹) significantly improved nutritional conditions (absorption of N, P, K, Fe, and Cu), growth parameters (e.g. shoot height, root length, shoot fresh weight, root fresh weight, and leaf number), and biochemical under control, low, moderate, and intense (0, 25, 50, and 75 mM NaCl, respectively) salinity stress conditions. Increased Fe in treated plants with coated Fe-NPs (especially 15 μM L⁻¹) decreased Na, increased N, P, K, Fe, and Cu, preserved their more photosynthetic pigments, and relative water content compared to other treated plants, and presented higher levels of key osmolytes, such as soluble sugars in the shoots and lower levels of soluble sugars in root and proline in root and shoot. Coated Fe-NPs may alleviate the adverse effects of salt stress on Ajowan growth by affecting plant biochemical properties, which is of economic and health significance.