Genotoxicity effects of silver nanoparticles on wheat (Triticum aestivum L.) root tip cells.

The distribution and use of nanoparticles have rapidly increased over recent years, but the available knowledge regarding their mode of action, ecological tolerance and biodegradability remains insufficient. Wheat (Triticum aestivum L.) is the most important crop worldwide. In the current study, the effects of silver nanoparticles (AgNPs) obtained from two different sources, namely, green and chemical syntheses, on chromosomal aberrations and cell division were investigated. Wheat root tips were treated with four different AgNP concentrations (10, 20, 40 and 50 ppm) for three different exposure durations (8, 16 and 24 h), and the different concentrations of the nanoparticles were added to the tested grains until the root lengths reached 1.5-2 cm. For each concentration, the mitotic indexes (%) were obtained from an analysis of ~ 2000 cells. The treated root-tip cells exhibited various types of chromosomal aberrations, such as incorrect orientation at metaphase, chromosomal breakage, metaphasic plate distortion, spindle dysfunction, stickiness, aberrant movement at metaphase, fragmentation, scattering, unequal separation, scattering, chromosomal gaps, multipolar anaphase, erosion, and distributed and lagging chromosomes. These results demonstrate that the root tip cells of wheat can readily internalize the AgNPs and that the internalized AgNPs can interfere with the cells' normal function.

Effect of foliar application of NPK nanoparticle fertilization on yield and genotoxicity in wheat (Triticum aestivum L.).

Two field experiments were conducted at the experimental farm of the Faculty of Agriculture (Saba Basha), Abess Region, Alexandria University, Egypt, over two harvest seasons (2016/2017 and 2017/2018) to study the effect of a nanoparticle fertilizer (Hyper Feed Amino NPs) compound on productivity and genotoxicity in two wheat cultivars compared with conventional mineral fertilizer. Total yield, its components, and yield components were measured. After harvest, grains of both cultivars were collected and germinated to produce root tip. Mitosis division and chromosomal aberrations were observed. Mitotic indexes (%) were obtained from an analysis of about 2000 cells. Root tips of control treatments showed normal mitotic stages, and the mitotic index ranged from 61.67 ±â€¯8.40 to 68.49 ±â€¯11.23%. Although fertilization with NPK NPs produced an increase in yield, and root-tip cells showed various types of chromosomal aberrations such as multinuclei, micronuclei, abnormal metaphase, stickiness, nucleus erosion, nucleus elongation, fragments, c-metaphase, chromosome deletion, c-chromosome, gab chromosome, lagging chromosome, distributed anaphase, bridge, abnormal telophase, telophase with unequal division, cell membrane damage, cell elongation, and increased nuclear content. The 100% NPK NPs treatment produced 35.79 ±â€¯9.32% and 38.98 ±â€¯4.22% abnormal cells in Sids 12 and Al-Rasheed, respectively. Our results demonstrate that wheat root tip cells readily internalize NPK NPs which can interfere with normal cell function.