Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Agr. Botany

The current study was performed on Asparagus officinalisL. (Mary Washington 500 W cultivar) of the family Asparagaceae, during the successive seasons 2017 {u2013} 2019 through three experiments; the 1st one goaled to display the effect of Zinc Oxide nanoparticles (ZnONPs) onAsparagus officinalis L. plant by using some morphological, histological, and biochemical parameters. Seeds were soaked in different concentrations of ZnO nanoparticles (0.5, 1, 3, 5, 10, 30, 50, 100, and 500 ppm) for 48h, in addition to Zn acetate Bulk (40 ppm) treatment and untreated control for comparison. The obtained results indicated that ZnO NPs treatment at the concentration of 500 ppm showed the highest values of all studied morphological characters of Asparagus plant with the exception of root length. In addition, a significant increase in catalase enzyme activity was observed when using a concentration of 500 ppm compared to the other treatments. The concentration of 3 ppm led to the highest stimulation effect for both types of flavonoids (Rutin and Myricetin), and the highest Naringenin and total flavonoids contents were detected when 5 ppm of ZnO NPs was used. With regard to the effect of Nano-Zinc on the anatomical features of the asparagus plant, it was found that there was a clear effect on the anatomical characteristics of the plant (root and stem) treated with a concentration of 500 ppm of ZnO NPs compared to plant treated with Zinc acetate at 40 ppm and untreated control plant.The2nd experiment (in vitro)aimed to evaluate the effect of Zinc Oxide nanoparticles (ZnO NPs) at different concentrationson callus biomass, cell suspensionviability (%) and flavonoids content in callus and suspension cultures of Asparagus plant. The results clarified that the treatment 10 ppm of ZnO NPs had the greatest callus fresh weight (8.01g) with a significant increase of 352.5% related to untreated control. The highest cell viability percentage wasrecorded at 10 ppm ofZnO NPs concentration on the 9th day. In callus culture, using ZnO NPs decreased the callus content of Rutin and total flavonoids compared with control. In suspension culture, the best flavonoid detected was Rutin compound (37.78 mg/100g) under10 ppm of ZnO NPs concentration with the third rank of total flavonoids content (94.59 mg/100g). The 3rd experiment (Antimicrobial effects)showed that the biomass and solvent types have an important role in inhibitingmicrobial activity.Root extracts were more effective than shoot extracts in most cases

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