الفهرس 
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Abstract
This study was carried out in the experimental farm of Agricultural Botany Department, Faculty of Agriculture, Mansoura University, Mansoura, Egypt, during the two growing seasons of 2007 and 2008 to minimize the harmful effects of salinity levels (2500, 5000 and 7500 ppm NaCl) by presoaking guar seeds in phytohormones (abscisic acid and salicylic acid) or plant vitamins (ascorbic acid and thiamine) at 50 or 100 ppm in upon their germination, plant growth, some aspects of metabolism, yield and its components as well as anatomical changes in (root, stem and leaf). In addition, investigate changes in the leaf upper epidermal cells in some treatment by SEM.: Increasing salinity levels up to 5000ppm decreased germination percentage seedling, root and shoot lengths, growth parameters photosynthetic pigments as well as shoots P and K concentration while, N concentration was increased. In addition, NaCl levels caused decreasing weight of seeds and pods / plant and decreased the number of pods. AsA or SA was more effective than other treatments to reduce the effect of salinity. The low level of NaCl enhanced P and k % and galactomannan content whereas, N, total protein and carbohydrates% were increased Moreover, AsA at 100 ppm gave the highest values in these parameters. Increasing NaCl decreased thickness of leaflet, root and stem Furthermore,SEM analyses of epidermal tissue showed differences between examined treatments in the shape and the size of epidermal cells, distribution of stomata, their position in epidermis and the structure of cuticle surface layers. Generally, structural differences in epidermal caused by salt concentrations and presoaking seeds by ABA or AsA. Furthermore, trichomes density and size increased with increasing salt stress but the size and number of stomata on guar leaflet surface treated with high salinity level (7500 ppm) was smaller than the untreated. Generally, phytohormones (SA) and plant vitamin (AsA or Thi) counteracted the harmful effect of salinity on guar seedling (growth against different salinity levels. In addition, AsA or SA was more effective than other treatment to reduce the effect of salinity. It may be concluded that for minimize the harmful effects of NaCl salinity and enhancing seed yield and its quality of guar plant, it is recommended to soak the seeds for 12 hours before sowing in phytohormone (salicylic acid) at 50 or100 ppm or plant vitamin (ascorbic acid) at 100 ppm.