Engineered silica nanoparticles alleviate the detrimental effects of Na+ stress on germination and growth of common bean (Phaseolus vulgaris)

During the past 10 years, exploiting engineered nanoparticles in agricultural sector has been rapidly increased. Nanoparticles are used to increase the productivity of different crops particularly under biotic and abiotic stresses. This study aims to test the ability of nanosilica (NS) to ameliorate the detrimental impact of Na+ with different concentrations on the seed germination and the growth of common bean seedlings. Five doses of Na+ have been prepared from NaCl, i.e., 1000, 2000, 3000, 4000, and 5000 mg L-1, and distilled water was applied as a control. Seeds and seedlings were treated with three different NS concentrations (100, 200, and 300 mg L-1). The results proved that Na+ concentrations had detrimental effects on all measured parameters. However, treating seeds and seedlings with NS improved their growth and resulted in higher values for all measurements. For instance, the addition of 300 mg L-1 NS leads to an increase of the final germination percentage,vigor index, and germination speed for seeds irrigated with 5000 mg Na+ L-1 by 19.7, 80.7, and 22.6%, respectively. Although common bean seedlings could not grow at the highest level of Na+, fortification seedlings with NS helped them to grow well under 5000 mg L-1 of Na+. An increase of 11.1 and 23.1% has been measured for shoot and root lengths after treating seedlings with 300 mg L-1 NS under irrigation with 5000 mg Na+ L-1 solutions, and also at the same treatment, shoot and root dry masses are enhanced by 110.9 and 328.0%, respectively. These results proved the importance of using NS to relieve the detrimental effects of Na+-derived salinity. This finding could be reinforced by low Na content which was measured in plant tissues after treating seedlings with 300 mg L-1 of NS.