الفهرس 
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Abstract
Two experiments were performed at Seed Technology Unit and Tag-El- Ezz Research Station in Dakahlia Governorate, Agric–Res-Center., Ministry of Agric during 2006 and 2007 season. This work was conducted to study the role of some antioxidant materials in alleviation the harmful effect of different salinity stress levels on maize cv. Single cross 122. Experiment 1: Four levels of salinity stress were used as follow: Tap water (320, 2000, 4000, 6000 mg/l) - Experiment 2: Two different soil areas were chosen: 1- 1840 mg/l. 2- 6080 mg/l. - Applied antioxidants were: Tap water, (Ascorbic acid, α- Tocopherol, Salicylic acid 250 mg/L), (Humic acid, Seaweed extracts 1000 mg/L). The grains were soaking in any of applied antioxidants for 6 hours before sowing and the plants were foliar sprayed with any of each applied antioxidants at 30, 45 and 60 after sowing under salinity stress levels.Three samples were taken at three different physiological stages (45, 60 and 75 day from sowing). All Chemical determination were investigated in shoot of maize plants in second sampling data (60 days after planting). The obtained main results of our investigations are :- Growth attributes: - Salinity stress levels slightly decreased all growth parameter with increasing salinity levels through the different physiological stages during the two experimental seasons (2006, 2007). Higher salinity stress level (6000 mg/l) was the most effective in decreasing growth parameters. - All applied antioxidants enhanced growth parameters of maize plant and caused slightly significant increase maize growth parameters at the different sampling periods throughout the experimental seasons. Ascorbic (ASA) and Salicylic acid (SA) were more effective in increasing growth of maize plant. Yield and its components: - The obtained results revealed that there are a negative relationship between high salinity stress levels and yield of maize plant during the growing seasons. The higher salinity stress level (6000 mg/l) was the most effective in decreasing yield and its components (ear length, ear diameter, number of rows/ear, number of grains/row and grain yield) of maize plant. - All applied antioxidants caused a slight increase of the yield of maize plant, ASA and SA were most effective in this respect. - It could by mention that applied antioxidants could be partially mitigate the harmful effect of salinity stress on yield of maize plant. ASA was the most effective in this respect, then SA, Toco., HA and SWE. Biochemical constituents : - Salinity stress levels and applied antioxidants as well as their interactions caused a slight increase in the contents of each proline, phenols, ascorbic and glutathione in the shoot of maize plant. 2- Applied antioxidants caused synergistic effect when combined with high salinity level (6000 mg/l) ASA and SA were the most effective in this respect. The data recorded showed that there is a positive correlation between the treatments of each salinity stress levels, applied antioxidants, their interactions and the activity of superoxide dismutase and ascorbic peroxidase. - The interaction of applied antioxidants with high salinity levels caused promoting effect on the enzymatic activity of SOD and APX. - ASA and SA treatments were the most effective in this respect. - Na content was increased by salinity stress levels while K content was decreased in the shoot of maize plant. High salinity level (6000 mg/l) was most effective in this respect. Na content was decreased while K content was increased due to the treatment with applied antioxidants as compared with control. Experiment 2: Applied antioxidants significantly increased growth characters, yield and its components (ear length and diameter, number of rows/ear, number of grains/row and grain yield) in the two salt soil areas especially (A1) compared with the control plants.- The recorded data show that applied antioxidant materials could alleviate the harmful effect of high soil salt stress levels on yield and its components of maize plant.- ASA and SA were more effective in this respect.