Seed priming with Calcium oxide nanoparticles improves germination, biomass, antioxidant defence and yield traits of canola plants under drought stress

Abstract

Recent advances in calcium signalling have proved that calcium plays a key role in mitigating abiotic stresses and strengthening the internal defence of plants. In the present research, calcium was imparted through seed nano-priming with calcium oxide nanoparticles (CaONPs) at concentrations of 25, 50, 75, and 100 ppm compared to control (0 ppm) under PEG-induced drought in the canola plants. During the germination experiment, seedlings were given drought conditions simulated by PEG-6000 treatment maintaining water potential at -0.15 MPa and pH of 5.5 supplemented with Hoagland solution at room temperature. As a control, no PEG-6000 was given. After the germination experiment, a pot experiment was conducted under artificial climate chambers. Seed nano-priming with 75 ppm CaONPs improved germination percentage and seedling fresh weight by 30% and 34% respectively under drought stress. Seed nano-priming with 75 ppm CaONPs increased the number of leaves by 16%, total chlorophyll contents by 28.9%, improved the number of pods per branch, number of seeds per pod, 100 seed weights, and yield by 29.99%, 73.076%, 35.13%, and 35.18% respectively under drought stress. Furthermore, the levels of antioxidant enzymes were improved and levels of stress indicators declined significantly. Present research recommends the use of CaONPs as pre-sowing treatments to the seed to improve the performance of canola plants.