Green synthesis and characterization of silver nanoparticles and its impact on the germination of Solanum lycopersicum L.

In the present investigation, silver nanoparticles (SNP) were synthesised using Dipteracanthus prostratus (Poir.) Nees, leaves extract and were characterised using UV-Visible spectroscopy, High resolution transmission electron microscopy (HR-TEM), and X-ray diffraction. The UV-Vis analysis of nanoparticles shows absorption peak at 412 nm. HR-TEM results showed them to be spherical - ellipsoidal in shape. XRD analysis revealed the metallic nature of the nanoparticles and the average grain size to be 20 nm. Preliminary study was carried out to examine the effect of SNP dosage (Control, AgNO ₃ , 0.1ppm, 1ppm, 10ppm, 50ppm) on the seed germination and growth of tomato (Solanum lycopersicum L.) plants. Each group had different dose responses to SNPs in terms of germination parameters and the measured growth characteristics. Germination percentage of 10ppm SNP treated seeds was marginally higher than the control plants whereas it decreased when the dosage of SNP was increased. Similarly, 1ppm and 10ppm SNPs had negligible negative impact on the tested growth parameters such as the ratio of fresh & dry weight, root length, shoot length and number of leaves of the tomato plant. At 50ppm, a significant reduction in all tested parameters was observed, a manifestation of the SNPs toxicity at higher concentration. Based on our study, low doses of bioreduced SNPs would be harmless to plant growth and development hence could be used in plant disease management strategies. Nevertheless more detailed studies are needed to assess the potential ecotoxicity and bioaccumulation in different trophic levels.