Particulate Nanoscale Silica Induced Novel Morphological and Biochemical Stimulus Effects in Chilli (Capsicum annuum L.)

Application of nanoscale materials in agriculture for various reasons, including plant nutrition, has been an interesting multidisciplinary research component. Among the plant nutrients, silica plays an important role as a quasi-essential nutrient besides enhancing resistance against disease and pests in the plant system. In the present investigation, we report the effects of foliar spray (field experiment) of varied concentrations (250, 500, and 750 ppm) of nanoscale silica (NSiO2) and osic acid (350, 700, and 1050 ppm) on structural and biochemical processes and yield in chilli (Capsicum annuum L.). NSiO2 was prepared using the sol–gel method and characterized by UV–vis spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The DLS analysis revealed the size (26.2 nm) and ζ-potential (−43.6 mV) of NSiO2. Significant increases in plant height, chlorophyll content, carotenoids, lycopene, and superoxide dismutase enzymatic activities were recorded with particulate NSiO2 foliar application at 750 ppm. Further, we are the first to report that foliar application of particulate NSiO2 led to the formation of a silicic acid layer on epidermal cells in chilli. Hence, foliar application of particulate nanoscale silica increases the flexural rigidity of epidermal cells, the chlorophyll content, carotenoids, lycopene content, and yield in chilli.