الفهرس 
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Abstract
A field study was conducted to evaluate the role of seed irradiation of sesame, soybean and sunflower for phytoremediation of contaminated soils. A study site was an agricultural field irrigated from wastewater of Bahr ElBqar, Belbis, Sharkia. Seeds of sesame, soybean and sunflower were exposed to gamma doses (0, 10, 25, 50, 100 and 200 Gy) emitted from cobalt 60 source. Throughout the plant growth and at the harvest stage, the 50 Gy dose in sesame and sunflower while the 100 Gy dose in soybean increased growth and yield parameters. Heavy metal contents (Pb, Zn and Cu) in roots, stems, leaves, oil and meal were analyzed. Concentration of the studied heavy metals (Pb, Zn and Cu) for the plants irradiated with different gamma doses was higher than those non irradiated (conrol). The flowering stage showed the highest concentration for the studied heavy metals than the vegetative stage. The higher phytoextration capacity of sesame plant was due to 50 Gy dose for Pb and Zn while the 10 Gy dose for Cu. Soybean plant showed the highest phytoextraction due to 100 Gy dose for Pb and Cu while the 25 Gy dose for Zn, for sunflower plant, this capacity was due to 50 Gy dose for Cu and Zn while the 10 Gy dose for Pb. Heavy metals in the oil of each plant were lower in comparison to that in the meal. Zinc was the most abundant among the detected heavy metals in the oil and meal followed by Pb and then Cu. Oil content and fatty acids composition were also affected. Oil content increased by irradiation in sesame and sunflower while irradiation does not affect oil content of soybean. Seed irradiation with gamma rays significantly affects photosynthetic pigment fractions, total free amino acids and soluble protein content. Also, it was observed accumulation of reactive oxygen species such as hydrogen peroxide and malondialdehyde as indicator of oxidative stress. Moreover, increasing gamma doses improved the activity of antioxidant either enzymatic or non enzymatic antioxidant. Enzymatic antioxidants represented by the activity of superoxide dismutase, peroxidase and polyphenol oxidase. Non enzymatic antioxidants represented by total free proline, phenolic and flavonoid compounds. Ascorbic acid content in sesame and sunflower plant was decreased in control and irradiated plants with the elapse of time; also significantly and gradually decreased by increasing gamma dose from 0-200 Gy. On the contrary, Ascorbic acid content in soybean plant was increased in control and irradiated plants with the elapse of time; also increased by increasing gamma dose from 0-100 Gy.