Abstract:
The present study focused on the interactive effect of titanium dioxide nanoparticles (TiO2 NPs) on rice (Oryza sativa) growth and changes in soil health for two contrasting soil textures (silt-loam and clay). For this purpose, the pot experiment was carried out, TiO2 NPs (0, 500, 750 mg kg-1) were applied through irrigation and plants were grown till the vegetative stage. After exposure period, plants were harvested; physiological parameters (root, shoot length; plant biomass), stress assay (H2O2 production, lipid peroxidation, leaf membrane injury index) and soil activities (microbial biomass C, dehydrogenase and soil respiration) were determined. The results showed an adverse effect of TiO2 NPs on plant growth and soil microorganisms in both soil textures at 750 mg kg-1. However, in clayey soil plants showed significant growth upon 500 mg kg-1 TiO2 NPs application as compared to silt-loam. Root and shoot lengths were 2.1- and 0.47 –folds higher, root-shoot biomass was 4.2- and 2.2 –folds higher in clayey soil as compared to silt-loam at 500 mg kg-1 TiO2 NPs treatment. H2O2 production, lipid peroxidation, and leaf membrane injury index were increased by 4.3-, 2.4-, and 1.9-folds in clay soil upon 750 mg kg-1 TiO2 NPs application. Likewise, at the same level of TiO2 NPs; microbial biomass, dehydrogenase, and respiration were decreased by 0.91-, 0.79-, and 0.78- folds respectively, in silt-loam soil. The results of the present study suggested that high concentrations of TiO2 NPs could negatively affect plant growth and soil enzymatic activities. Therefore, detailed work is still required on the plant-soil-TiO2 NPs interactions to assess their toxic influence before commercializing them as nano-fertilizers.
