Figure 8.

Working model showing how CaO NPs supplementation reduce As-induced phytotoxicities in barley seedlings. Initially, CaO NPs, after entering plant body, activate enzymatic antioxidants (i.e., SOD, POD, and CAT), which in turn help barley seedlings to manage metal-induced oxidative stress. Further, CaO NPs application supports plant growth by improving Ca²⁺ ions homeostasis and photosynthesis. In addition, CaO NPs reduce uptake, mobilization, and acropetal translocation of As by decreasing the transcript abundance of As transporting genes (HvPHTs), which ultimately helps plant to reprogram its normal physiological and developmental processes.