Facile biosynthesis, characterisation and biotechnological application of ZnO nanoparticles mediated by leaves of Cnidoscolus aconitifolius

The present study synthesised and characterised zinc oxide nanoparticles (ZnO NPs) using spinach tree, Cnidoscolus aconitifolius and investigated its potential use as nanofertilizer. The synthesised nanoparticles showed UV–Vis absorption peak at 378 nm which is a feature of ZnO NPs. FT-IR analysis further revealed the presence of O-H stretching, C = C bending, O-H bending and C-N stretching functional groups of the stabilising action of the plant extract on the surface of the nanoparticles. SEM images displayed the shape of NPs to be spherical whereas TEM images showed their distribution sizes to be 100 nm. Synthesised ZnO NPs were used as a nano fertilizer on Sorghum bicolour plant. An increase in the shoot leaf length with an average length of 16.13 ± 0.19 cm as compared to the control group of 15.13 ± 0.07 cm was observed. The rate of photosynthesis also showed a significant increase with total chlorophyll content of 0.2806 ± 0.006 mg/mL as compared with control of 0.2476 ± 0.002 mg/mL. The activity of antioxidative enzymes was measured with an increase in the specific activity of SOD in the plant when ZnO NPs were used over NPK whereas, the specific activities of CAT were similar in all cases.