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BACKGROUND: One of the major abiotic stressors that have a serious effect on plant growth and productivity worldwide is the salinity of soil or irrigation water. The effect of foliar application of magnetite nanoparticles (size = 22.05 nm) at different concentrations (0, 0.25, 0.5, and 1.0 ppm) was investigated to improve salinity tolerance in two wheat cultivars, namely, Misr1 (Tolerant) and Gimmeza11 (Sensitive). Moreover, toxicological investigations of magnetite oxide nanoparticle in Wistar albino rats were estimated. RESULTS:The magnetite nanoparticles positively affected growth, chlorophyll, and enzymatic antioxidants such as superoxide dismutase (SOD), stimulating reduced glutathione and improving the aggregation of several polypeptide chains that may be linked to the tolerance of saline stress. In contrast, magnetite nanoparticles reduced malondialdehyde (MDA). Inverse sequence-tagged repeat (ISTR) assay of DNA molecular marker showed the change in band numbers with the highest polymorphic bands with 90% polymorphism at primer F3, B5 and 20 positive bands in Gimmeza11 with 0.5 ppm magnetite nanoparticles. In the median lethal dose (LD 50 ) study, no rats died after the oral administration of magnetite nanoparticle at different doses. Therefore, the iron oxide nanoparticle was nontoxic when administered orally by gavage. CONCLUSION: Magnetite nanoparticles partially helped to alleviate the effects of salt stress by activating growth, chlorophyll content, SOD, glutathione, and soluble proteins in two wheat cultivars (Misr1 and Gimmeza11) and decreasing MDA content.

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Potato is a very sensitive to drought stresses, necessitates specific amounts and quality of water. Making substantial changes to increasing tolerances are not easily due to their narrow genetic base. Researchers developed many techniques to reduce the effects of abiotic stress. In current work we studied the effect Nano Particles of Zinc dioxide (ZnO-NPs) and Magnetite (Fe3O4-NPs) at (0.0, 2.5, 5.0 ppm) in elevating the negative effect of drought stress (Sorbitol) at (0.0, 1, 2, 3, 4 Mm) on micropropagation, microtuberization and some biochemical characters, using two potato cultivars (Almond, and Picasso). Maximum mean values were achieved by Almond cultivar and by ZnO-NP in most vegetative, harvesting parameters in vitro. In experiment 1: increases sorbitol levels caused reduction in all parameters inversely, and growth was stopped completely by (0.40) M which considered as a lethal dose to potato explants for both cultivars. In experiment 2: results illustrated that, significant improved due to add nanoparticles of ZnO or Fe3O4 at two concentrations (2.50 and 5.00) ppm on all morphological, harvesting parameters at 0.40 M and 0.3 M of sorbitol. About secondary metabolites: the maximum record of flavonoids (querecetin and kaempferol) and antioxidant capacity was achieved by Almond with sorbitol 0.3M. Almond also recorded the maximum mean of quercetin, kaempferol and, DPPH scavenging activity was decreased in sorbitol 0.3M for both NPs treatments. At 0.4M, secondary enhanced accumulation metabolites and scavenging activity especially at ZnO NPs (5 ppm) and Fe3O4 NPs (2.5 ppm), in quercetin and kaempferol with Fe3O4-NPs (5.0 ppm).