الفهرس 
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Abstract
Common bean (Phaseolus vulgaris L.) is one of the most important vegetable crops in Egypt. It has long been recognized to be either sensitive or only moderately tolerant to salinity. The increasing demand on water for reclamation lands raised the necessity of using the saline water either from wells as a source for irrigation. The idea of using the plant growth regulators to alleviate adverse effects of salinity stress on higher plants was put forward quite early. So, two pot experiments were conducted in two successive summer seasons; 1999 and 2000 under the green house of horticultural researches station; ElMansoura City; Dakahlia governorate to find out mainly the effects of salinity and remedy treatments (ATP and Cytokinin) as well as soil conditioner (Hydrogel), on the growth, yield, yield components and chemical constituents of common bean cultivars, Nebrasca and Bronco. The experiment included 32 treatments, which were the simple possible combination between; two cultivars of common been plants (Nebrasca and Bronco cvs.); four treatments of irrigation at different stages of plant growth including, three treatments with saline water at the rate of 3000ppm NaCl and the fourth with tap water as a control treatment, and three remedy treatments i.e. Hydrogel, ATP or Cytokinin as well as the untreated. Before sowing, soil mixed with hydrogel at the rate of 0.15% w/w. the remedy treatments (ATP and BAP) were foliar applied 3 times by 7days interval beginning 40 days after sowing at the rates of 25ppm and 10ppm, respectively. Other agriculture practices for common bean plant were done as recommended. All obtained results were subjected to a complete randomized block design with three factors. The obtained results could be summarized as follows: 1. Vegetative growth characteristics: 1.1. Plant height (cm/plant). In both seasons, Nebrasca cv. was taller than Bronco cv. using of saline water at any period of plant growth significantly reduced the height of the plant for the two cv. An addition of remedy treatments significantly increased the height of the two cultivars comparing with the untreated treatment. Foliar spraying of cytokinin at any period of irrigation with saline water was superior for increasing the height of common bean cultivars. 1.2. Number of leaves per plant: There were no significant differences between Nebrasca and Bronco cvs. on this character in both seasons. Using saline water at the rate of this study had a depressive effect on the number of leaves per plant at any period of plant growth stages. An application of different remedy treatments under saline conditions has been corrected the effect of salinity stress and significantly increased this character and this trend was more pronounce of the treatment of cytokinin. 1.3. Leaves area (cm2 / plant) Nebrasca cv. tended to have more leaves area than Bronco cv. Under the different periods of irrigation with saline water, leaves area of common bean cvs. were significantly decreased comparing with the control treatment. The progressive decrease in leaves area of common bean cvs. can be corrected by an addition of various remedy treatments studied; specially foliar spraying of cytokinin. 1.4. Fresh weight (g/plant) Nebrasca cv. had higher values of fresh weight than Bronco cv. in both seasons. Irrigation of the common bean cvs. with saline water at any period of plant growth had a significant decrease in the values of fresh weight in both seasons. The interaction between the irrigation with saline water and an addition of different remedy treatments showed a significant effect in the two seasons. The highest fresh weight value was obtained from the plants treated with cytokinin followed by the treatments of ATP and hydrogel, respectively as compared to the control treatment. 1.5. Dry weight (g/plant) There were significant differences in dry weight fro whole plant as well as its different parts between the two cvs. of common bean plants. Treatments of common bean cultivars with saline water at any period of plant growth significantly decreased the average values of dry weight of the leaves, stems and roots as well as the whole common bean plant. Mixing the soil with hydrogel or foliar spraying of ATP or cytokinin on common bean cvs. was corrected the adverse effect of saline water and significantly increased the average values of dry weight (g/plant) for whole plant and its parts. 2. Photosynthetic pigment contents: The mean values of chl. (a), chl. (b) and total chl. (a+b) in Nebrasca cv were higher than the same values obtained from Bronco cv. .Salinity irrigation water decreased the level of chlorophyll contents relative to the control treatment. On the contrary, an addition of different remedy treatments under investigation has been corrected the adverse affect of the values of chlorophyll constituents due to irrigation with saline water at any system (B, C or D treat.) as compared with the untreated. 3. Mineral composition Nebrasca cv. had more phosphorus % and potassium % than Bronco cv. while, the average values of Ca, Mg and Na% contents in the leaves of Bronco cv. significantly increased than those obtained from Nebrasca cv. in both seasons. On the contraries the differences between the two cultivars had no any significant effect on N% during both seasons. Irrigation with saline water at any period of plant growth under study significantly increased the contents of common bean leaves from N, Ca, Mg, K and Na (as %) while the same effect had no significant effect for P% during the both seasons. As for the effect of an application of remedy treatments under saline condition, the trend of Ncontent in the two cultivars was not clear in both seasons while a simulative effect was happened for P and K%. On the other hand, the interaction effect between salinity and remedy treatments had a depression effect on Ca, Mg and Na contents in the leaves of common bean cultivars. 4. Proline and carbohydrate accumulation Common bean cultivars irrigated with saline water in combination with the application of different remedy treatments tended to accumulate less proline content values than those obtained from the plants grown under saline conditions only. On the contrary the adversely effect was realized for the leaves contents of carbohydrates for common bean leaves at green maturity stage. 5. Yield components 5.1. Date of flowering For the two tested cultivars; the days required to appearance of the first flower in Nebrasca cv. were shorter than that required for bronco cv. in both seasons. Using saline water threshold in the treatment of B or C led to acceleration in the flowering process of common bean plants, while the same character for the plants received saline water after flowering stage did not affect significantly during both seasons. An addition of various remedy treatment for the plants received saline water after 21 days from sowing (Btreat.) led to an increase in the date of flowering while, the same character had no significant effect for the treatments of A, C or D. 5.2. Date of podding Bronco cv. has been required number of days to appearance the first pod longer than Nebrasca cv. The plants received saline water either after 21 days from sowing (Btreat) or as exchangeable irrigation (Ctreat) significantly decreased this character compared with the control treatment. While, the plants irrigated with saline water after flowering stage (Dtreat.) had no significant effect on the same one in both seasons. The number of days required to appearance of the first pod had no significant differences as affected by the treatment of A, C or D compared with an addition of various remedy treatments studied, while the same effect significantly increased when the common bean cvs. received saline water after 21 days from sowing (Btreat.). 5.3. Number of flowers per plant Nebrasca cv. had higher records as for this character than Bronco cv. in the 2nd season while this effect was insignificant in the 1st season. Salinity treatments caused a marked decrease in the average number of common bean flowers per plant as compared with the control treatment. There were no