الفهرس 
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Abstract
Two seasons of pot experiment were carried out during 2001/2002 and 2002 /2003 growing season at plant nutrition Lab., Agriculture research center , Dakahlia governorate. The work aims to study the effect of soil salinity on root cation exchange capacity of two wheat varieties ( Sahka 92 and Gemmiza 9 cultivars ) in relation to dry matter production and nutrients concentrations and it?s uptake of plant organs. Non saline soil was collected from ELGawashna village Sharkia governorate , then artificially salinized by adding soil solution containing a proper amount of chloride salts (1 NaCl : 1CaCl2 by weight ) to represent four levels of soil salinity ( control , 0.2 , 0.4 , and 0.6 %). And the obtained results can be summarized in : 1 slight soil salinity levels ( 0.2% ) enhance wheat seedling emergence while soil salinity above 0.2% ( 0.4 and 0.6% ) to a large extend delay that . 2 The highest root growth rate was observed between the end of tillering stage and flowering stage . 3 At flowering stage , root cation exchange capacity of wheat plant reached to 122.68% and 138.36% of that at tillering and maturity stages , respectively . 4 Root cation exchange capacity positively correlated with root weight in each physiological growth stages where a negative correlation was found between root cation exchange capacity and root weight of wheat plant along plant live. 5 A lower increase in grain yield ( 5.08% ) with Gemmiza 9 cultivar compared to that of Sakha 92 cultivar ( 6.31% ) due to soil salinity increase from control ( 0.0804% ) to 0.2% , where , soil salinity level of 0.6% caused a severe reduction in grain yield of Gemmiza 9 ( 36.90% ) than that occurred with Sakha 92 cultivar ( 29.00% ) compared with control . 6 Soil salinity levels high significantly affect nitrogen uptake by wheat grains, where, soil salinity level of 0.2% increase grain nitrogen uptake by 13.06% compared with control .On the other hand 0.4 and 0.6% soil salinity decreased grain nitrogen uptake by 13.17 and 44.79%, respectively. 7 The gradual increase in soil salinity level ( control , 0.2 , 0.4 and 0.6% ) significantly decreased nitrogen , phosphorus and potassium concentration of wheat shoots at any physiological stage . 8 At any soil salinity level, the differences between grain nitrogen uptake means of variety were highly significant and the highest values were found with Sakha 92 cultivar.