Silver nanoparticles (AgNPs) biosynthesized using pod extract of Cola nitida enhances antioxidant activity and phytochemical composition of Amaranthus caudatus Linn

Multi-walled carbon nanotubes (CNTs) can affect plant phenotype and the composition of soil microbiota. Tomato plants grown in soil supplemented with CNTs produce two times more flowers and fruit compared to plants grown in control soil. The effect of carbon nanotubes on microbial community of CNT-treated soil is determined by denaturing gradient gel electrophoresis and pyrosequencing analysis. Phylogenetic analysis indicates that Proteobacteria and Bacteroidetes are the most dominant groups in the microbial community of soil. The relative abundances of Bacteroidetes and Firmicutes are found to increase, whereas Proteobacteria and Verrucomicorbia decrease with increasing concentration of CNTs. The results of comparing diversity indices and species level phylotypes (OTUs) between samples showed that there is not a significant affect on bacterial diversity. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sustainable use of nanotechnology for agricultural practice requires an understanding of the plant's life cycle and potential toxicological impacts of nanomaterials. The main objective of this study was to compare the impact of TiO2 and ZnO nanoparticles of similar size (25 ± 3.5 nm) over a range of concentrations (0 to 1000 mg kg(-1)) on translocation and accumulation of nanoparticles in different plant sections; as well as to establish physiological impact on tomato plants. The results indicated that there is a critical concentration of TiO2 and ZnO nanoparticles upto which the plant's growth and development are promoted; with no improvement beyond that. Aerosol mediated application was found to be more effective than the soil mediated application on the uptake of the nanoparticles was in plants. A mechanistic description of nanoparticle uptake, translocation and resultant plant response is unraveled. The present investigation demonstrates the concept of nanoparticle farming by understanding plant - nanoparticle interaction and biodistribution.

Metal nanoparticles can potentially be used as tools for engineering biological redox reactions. Present study underlines the effect of silver metal nanoparticles (at 0, 25, 50, 100, 200 and 400 ppm) on the growth and antioxidant status of 7-day-old Brassica juncea seedlings. Fresh weight, root and shoot length, and vigor index of seedlings is positively affected by silver nanoparticle treatment. It induced a 326 % increase in root length and 133 % increase in vigor index of the treated seedlings. Improved photosynthetic quantum efficiency and higher chlorophyll contents were recorded in leaves of treated seedlings, as compared to the control seedlings. Levels of malondialdehyde and hydrogen peroxide decreased in the treated seedlings. Nanoparticle treatment induced the activities of specific antioxidant enzymes, resulting in reduced reactive oxygen species levels. Decrease in proline content confirmed the improvement in antioxidant status of the treated seedlings. The observed stimulatory affects of silver nanoparticles are found to be dose dependent, with 50 ppm treatment being optimum for eliciting growth response. Present findings, for the first time indicate that silver nanoparticles promote the growth of B. juncea seedlings by modulating their antioxidant status.