Magnesium Oxide Nanoparticles (MgO-NPs) Alleviate Arsenic Toxicity in Soybean by Modulating Photosynthetic Function, Nutrient Uptake and Antioxidant Potential

The consequences of climate change, and the increased accumulation of metalloids, like arsenic (As), in the environment, are significantly affecting crop performance and yield. Arsenic interferes with various plant biochemical and physiological processes, which result in diminished plant growth and development. Magnesium oxide nanoparticles (MgO-NPs) can improve plant growth and contribute to plant tolerance of heavy metal/metalloid toxicity. During current research, the efficacy of MgO-NPs was assessed for lessening arsenic (As) toxicity in soybean plants. In our experiment As uptake, plant growth, antioxidant enzyme activity, nutrient content, photochemical efficiency and photosynthetic performance were evaluated with/without exogenous application of 500 mg L−1 MgO-NPs in the presence/absence of 150 µM As in soybean plants. Foliar application of MgO-NPs, in the presence of As, enhanced plant height and dry weight by 17% and 15% respectively, and improved net photosynthetic rate by 12.9%, stomatal conductance by 13.4%, intercellular CO2 concentration by 15.3% and transpiration rate by 14.7%, as well as nutrient uptake and photosystem II (PSII) efficiency. In contrast, it decreased As uptake and oxidative stress as evaluated with hydrogen peroxide (H2O2) and lipid peroxidation (MDA). Hence, field tests may be implemented to formulate MgO-NPs use in agriculture, in order to obtain sustainable crop production in arsenic-contaminated soils.