Synthesis of magnetic nanoparticles and their effects on growth and physiological parameters of Calotropis procera seedlings

The present study was carried out to elucidate effects of synthesized magnetic nanoparticles (MNPs) on morphological and physiological parameters and main essential oil components of Calotropis procera seedlings. For this purpose, 21-day-old seedlings grown under hydroponic conditions were treated by the different MNP concentrations (0, 50, 100, 150, and 200 mg L^-1). The results showed that the growth parameters, chlorophyll pigments, soluble sugars, and total proteins significantly increased in leaf under MNP treatment, except for the root length. As compared to the control, MNPs induced a substantial change in the activities of antioxidant enzymes, H₂O₂, and malondialdehyde contents. Ascorbate peroxidase activity showed a meaningful increase in leaf treated with 200 mg L^-1 MNPs, while superoxide dismutase activity and concentration of H₂O₂ conspicuously decreased relative to the control. Moreover, MNPs enhanced geranial, 1,8-cineol, a-phellandrene, citronellal, camphor, and terpinen-4-ol contents as major components. These results suggest that MNPs could be a promising method of iron application in agricultural systems. Regarding the effects of MNPs, 200-mg L^-1 MNPs were most effective on the production of main essential oils and plant growth that could serve as a favorable elicitor for plant improvement.

Investigation of ZnO nanoparticles on proline, anthocyanin contents and photosynthetic pigments and lipid peroxidation in the soybean

The interaction between nanoparticles and plants is inevitable. In this study, the effect of different concentrations of ZnO nanoparticles synthesised using olive extract on the soybean was studied. The soybean seeds were cultured in a Hoagland medium containing agar which was treated different concentrations (0, 200 and 400 ppm) of ZnO nanoparticles. After 21 days, the plants were harvested and the parameters of proline, anthocyanin, malondialdehyde (MDA), hydrogen peroxide (H2O2), chlorophyll and carotenoid contents and phenylalanine ammonia-lyase (PAL) and catalase (CAT) activity in soybeans (Glycine max) were measured. The results showed that the levels of chlorophyll a and b and carotenoid at concentrations of 200 and 400 ppm in comparison with control decreased, while carotenoid content at 200 ppm concentration at a concentration of 400 ppm was not significant. The level of anthocyanin and PAL activity increased with increasing concentration of nanoparticles, while proline content decreased. By increasing the concentration of ZnO nanoparticles, the content of MDA and hydrogen peroxide increased compared to control but CAT activity did not change significantly. This research suggests that ZnO nanoparticles synthesised using olive extract in soybean plants may be toxic by reactive oxygen species production.

Green synthesis of ZnO nanoparticles by Olive (Olea europaea)

Green synthesis of nanoparticles is superior to physical and chemical methods as it is environment-friendly and cost-effective. The present study was carried out for inducing nanoparticles synthesis by zinc nitrate in the leaves extracts of olive. Further leaves extracts were evaluated for antiradical scavenging activity by 1, 1-diphenyl-2-picryl-hydrazyl assay. Morphological and structural properties of the synthesised ZnO nanoparticles have been characterised using UV-Vis spectrophotometer, FTIR, TEM, XRD and dynamic light scattering (DLS) analysis. Further, zinc oxide nanoparticles were evaluated for antiradical scavenging activity by capacity of total antioxidant assay. Synthesised ZnO nanoparticles were confirmed by the absorption maxima at the wavelength of 370 nm. TEM image revealed that ZnO nanoparticles were spherical with average size 41 nm. FTIR investigation suggested that the flavonoids, glycosides, proteins and phenols molecules can play an important role in the stabilisation of ZnO nanoparticles.