Green synthesized nano silica: foliar and soil application provides drought endurance in Eleucine coracana

Abstract

Climate change scenarios will lead to drought like conditions. Drought impairs growth and productivity of Eleucine coracana, a crop of high nutritional value and socio-economic importance. Various approaches to alleviate the deleterious impacts of drought are under consideration. Contemplated use of nanotechnology may resolve environmental concerns by providing rational elucidations. Green synthesis of silica nanoparticles (NPs) was done using leaf extract of Thuja orientalis and they were characterized using standard characterization techniques. The NPs were approximately 78 nm in size. A pot experiment was conducted to study the effect of silica NPs at different concentrations (50, 100 and 200 mg L⁻¹) on drought recovery of PES-400, a drought sensitive variety of Eleucine coracana. The NPs were applied via foliar spray and root application. The morpho-physiological and biochemical responses of Eleucine coracana were recorded at the vegetative stage after treatment with silica NPs. The plant height, root length, leaf area, relative water content, free proline, ascorbate, total phenolics and flavonoid content improved with treatment of 50 and 100 mg L⁻¹ silica NPs as compared to stressed plants. A decrease in malondialdehyde content was observed. The specific activity of superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase and glutathione reductase also improved upon application of silica NPs. No significant improvement was observed with 200 mg L⁻¹. Both modes of application displayed similar effects. Our research disclosed that silica NPs played a role in promoting drought recovery in PES-400 by improving its morpho-physiological features and activating its antioxidant system. They can be recommended for use at 50–100 mg L⁻¹ concentrations in drought prone agricultural zones for stimulating tolerance in crops. They will also boost food security in the era of global warming.