الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Heavy metal pollution became increasingly a serious environmental problem. Pollution of soil with heavy metals can adversely affect plant growth hence, its productivity and could be transmitted to humans via the food chain causing health hazards. Aiming at searching for some applicable treatments which can alleviate the stress imposed by elevated levels of the heavy metals (HMs): Cd, Cu, and Pb on some economicallyimportant fabaceous plants, three experiments were carried out. The first experiment was conducted to study the effects of HMs on seed germination and seedling growth of faba bean and pea and the possible alleviation effects of three antioxidants (AOs) i.e. ascorbic acid (AsA), glutathione (GSH) , and gastocopherol (T) as well as that of salicylic acid (SA). The results of this experiment indicated that seed germination quality , as evidenced by germination percent and mean germination time, and seedling growth, as represented by length as well as fresh and dry weight of both shoots and roots were enhanced due to AOs as well as SA under HMs stress, and AOs were more efficient in this respect. In addition, root tolerance index and membrane stability index were higher in AOstreated, HMsstressed seedlings. The higher level of AOs (20 mg L1) was more effective. Generally, seed germination and seedling growth were less sensitive to HMs stress in faba bean than in pea. The second experiment was carried out to evaluate the effects of AOs on the plant?s antioxidative defence system and certain other sressrelated metabolites of HMsstressed bean and pea plants. The results of this experiment indicated that treatment of HMsstressed plants with either AsA, GSH or T , especially at 50 mg L1, can activate the plant?s antioxidative defence system by elevating the levels of endogenous antioxidants and the activitiy of the antioxidant enzymes thereby reduced HMsinduced oxidative stress. AOs treatments also reduced the accumulation of H2O2 and ABA whereas increased the levels of the growth stimulators, IAA and GA3 in HMsstressed plants. The third experiment was conducted to test the alleviation effects of the most efficient AOs, AsA and GSH based on the results of the 1st and 2nd experiments, both added at 50 mg L1 , in comparison with that of the mycorrhizal fungus Glomus mosseae (Gm) on yield and its quality and some yieldcontributing biochemical constituents of bean and pea plants. The results indicated that AOs as well as Gm enhanced the tested yield contributing biochemical constituents hence, increased yield and enhanced its quality by increasing AsA conc. as well as protein percent and decreasing HMs accumulation in HMsstressed plants. Gm was, generally, more effective than AOs in this respect. Within AOs, the alleviation effect of GSH was superior to that of AsA. The physiological bases of the recorded treatment?s effects were discussed. It was concluded that the treatment with GSH or the inoculation with Gm, depending on the economic feasibility, is recommended to enhance plant HMsstress tolerance, and to reduce HMs accumulation in the consumptive plant parts. It was also recommended that new mycorrhizal inoculation methodologies should be developed to make possible seed inoculation which will facilitate mycorrhization of largescale cultivations, as an economic mean for reducing HMs stress on economic plants