B., FAKRUDINL., SUMUKHAH. B., LINGAIAHB. S., VENKATESHAS., ANIL KUMAR2020-11-202020-11-202015-06UHS13PGM381https://krishikosh.egranth.ac.in/handle/1/5810155406Green synthesis of gold, silver and copper nanoparticles was attempted using hibiscus, lemongrass, neem, tamarind and tulsi leaf extract. All tested plant extracts effectively acted as reducing agents and yielded gold, silver and copper nanoparticles within the size range of 54.96 nm to 338.4 nm. There were significant differences recorded among the nanoparticles and their concentrations on various qualitative and quantitative characters of tomato cv. Arka Vikas. Green house pot experiment of tomato plants treated with 10 ppm gold nanoparticles could successfully improve phenotypic attributes in traits such as plant height, number of branches per plant, number of flower clusters per plant, number of fruits per plant, yield per plant, pericarp thickness and total soluble solids and a similar trend was also observed in Arabidopsis. Differential up and down regulation among tested microRNAs and their cognate genes was observed in leaves of Arabidopsis plants exposed to different concentrations of nanoparticles. The miR397a (10.9 fold) and miR399e/f (0.37 fold) recorded up regulation and miR171 (0.47 fold) was found down regulating in leaves tissues sprayed with 10 ppm gold nanoparticle. Three miRNA cognate genes viz., UBC 24 (11.44 fold), SCL6-III (7.36 fold) and SCL6-IV (4.79 fold) were up regulated with the exposure of 10 ppm gold nanoparticle treated leaf tissues of Arabidopsis thaliana. Up regulation of miRNA cognate genes, PPR (1.21 fold) and AGO1 (9.5 fold) and down regulation of miRNA cognate genes UBC24, APS1, APS4, LAC2, LAC17, SCL6-III and SCL6-IV was observed in leaves exposed to 100 ppm zinc oxide nanoparticles.EnglishThesis