Abstract
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).