الفهرس 
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Abstract
A greenhouse experiment was carried out on Vicia faba L. (cv. Giza 716) in order to investigate the inhibitory effects of Cu stress and to evaluate the impact of seed priming with IAA as chemical tool, and the natural yeast extract in alleviating the deleterious effects of Cu stress as compared with the prospective effect of ZnO NPs. Firstly, the ZnO NPs were green synthesized using Coriandrum sativum leaf extract and the resultant nano powder was used to prepare different concentrations of the nano ZnO solutions (10, 50, 100 ppm) in distilled water. The yeast extract was prepared using the dry yeast powder, which was first activated with addition of carbon source, and then used to prepare 25, 50, and100% of this extract. However, IAA solution was prepared with concentrations of 0.1, 0.3 and 0.5 mM. The sub-lethal concentration of Cu and the effective concentrations of IAA, yeast and ZnO NPs, in addition to their efficient seed priming periods were determined in Vicia faba seedlings in some preliminary experiments. Depending on the results of these preliminary experiments, the sub lethal concentration of CuSO4was estimated to be 100 mM, the effective concentration of IAA was 0.1 mM, and that of yeast extract was 50%, while that of ZnO NPs was 100 ppm. Concerning the effective soaking time of priming, it was selected to be 10 hrs for IAA and yeast and 6 hrs for ZnO NPs. The main experiment was achieved during the growing season of Vicia faba in November. Seeds with uniform size and shape were selected and divided into five groups; the first and second groups were soaked in distilled water for 10 hrs. The third and fourth groups were primed by soaking either in 0.1 mM IAA or 50 % yeast extract, each for 10 hrs. The fifth group was soaked in 100 ppm ZnO NPs solution for 6 hrs. The soaked seeds of each group were sown in clay-sandy soil (2:1w/w) in plastic pots and left to grow under the normal conditions for 7 days; while they were irrigated with tap water once every two days. On the 7th day, all the groups were irrigated once with 100 mM CuSO4 till 60 % field capacity except the control which was irrigated with water. Meanwhile, the plants were subjected to extra doses of stress treatment (100 mM CuSO4) at the day 40 and 60 of growth, after which they were irrigated normally with water twice weekly till the end of the experiment. Additionally, at the age of 40 and 60 days, foliar application using solutions of 0.1 mM IAA, 50% yeast extract, or 100 ppm ZnO nanoparticles were sprayed uniformly each for its specific treatment; while distilled water was sprayed to the control and the Cu stress treatment. The harvesting was carried out at 3 growth stages; seedling (21-day-old), preflowering (50-day-old) and yield stage (150-dayold).