Modern nanotechnology has been credited as one of the most significant inventions of the 21st century. Many agricultural disciplines have been affected by nanotechnology in agriculture. Pest control based on natural compounds needs to be enhanced, and enhancing plant growth under climate change conditions, with increasing periods of drought in many countries, is a very vital aim. Thus, the effect of curcumin nanoparticles (Cu-NPs) and glycyrrhizic acid nanoparticles (GA-NPs) as a foliar application under water deficit on natural infestation with the two-spotted spider mite Tetranychus urticae, plant growth and yield, anatomical and chemical parameters were investigated during this study. The obtained results revealed that drought stress over the two studied seasons significantly increased the population of T. urticae and decreased all morphological and yield characteristics. The application of three mM GA-NPs reduced the mite population average by 39% while using the same concentration of Cu-NPs caused a 33.9% reduction percentage under drought stress. Using 1 mM GA-NPs gave the highest averages of plant height, number of branches, and leaves/plant fresh and dry weight. Moreover, the number of pods, 100 seed weight and seed yield (kg/ha) increased significantly as a result of spraying with GA-NPs under water deficit. From the results, water deficit decreased the values of the leaf and stem anatomical parameters. Treatment with Cu-NPs or GA-NPs under drought stress increased the thickness of mid-vein, xylem, and phloem tissues. Likewise, such treatment increased stem diameter due mainly to the increase in the thickness of cortex, phloem, and xylem tissues compared with the control. Spraying plants with GA-NPs at 1 mM increased the percentages of nitrogen, phosphor, and potassium in seeds in addition to total chlorophyll. Moreover, glutamate, aspartate, leucine, arginine, Lysine, glycine, tyrosine, tryptophan, and methionine concentrations did not differ significantly (p > 0.05) in response to all the studied levels of Cu-NPs or GA-NPs either under normal irrigation or drought condition. In light of these findings, researchers and producers should apply and test both Cu-NPs and GA-NP as nano-fertilizer natural sources on economically viable crops.
Keywords: Tetranychus urticae; anatomy; drought; growth parameters; nano-curcumin; nano-glycyrrhizic acid; soybean.