الفهرس 
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Abstract
The present investigation was conducted during 2013 and 2014 growing seasons in order to evaluate the influence of different mineral nutrients, growth regulators and an antitranspirant in reducing salinity hazards in grapevine and olive seedlings. One year old Thompson seedless grapevine and Picaul olive seedlings were selected in this study. The seedlings were planted in black polyethylene bags filled with about 2 kg of clay loam soil. In mid – June of both 2013 and 2014 seasons, the experimental plants were divided into three groups and each group was irrigated with saline solution having one of the following concentrations: zero (tap water), 2500 or 5000 ppm sodium chloride. Each group receiving one of the three saline levels were again sub-divided to seven sub-groups, and each sub-group received one of the following treatments: 100 ppm nitrogen, 50 ppm phosphorus, 100 ppm potassium, 100 ppm gibberellic acid, 250 ppm paclobutrazol, 5% paraffin, oil antitranspirant or untreated control. This factorial experimental was designed randomized complete design, in which the main factor was allocated to the salinity levels and the sub-factor was allocated for fertilization or spray treatments. Thus, 84 seedlings from each fruit species were used in either year of study (3 salinity levels x 7 fertilization or spray treatments x 4 replicates = 84 seedlings from each fruit species in each experimental seasons).
The effect of the different nutritional, growth regulators and antitranspirant treatments as well as that of the NaCl salinity levels on the growth rate, total leaf area, stem cross- sectional area, total, top and root dry weights as well as top: root dry weight ratio was measured. In addition, the effect of the different treatments on leaf and root mineral composition (N, P, K, Ca, Mg, Na, Cl, Fe, Mn and Zn), total, a and b leaf chlorophyll, leaf and root carbohydrate fractions (total carbohydrates, starch and reducing, non reducing and total soluble sugars), alpha total free amino acids as well as total phenolic compounds were also determined. The results of the present study, during both experimental seasons, could be summarized as follows: I. Growth Indices: 1. Raising the salinity level of the irrigation solution from zero to either 2500 ppm or 5000 ppm NaCl caused a significant reduction in the seedling growth rate, total leaf area and top, root and total dry weights of grapevine and olive seedlings. The magnitude of reduction in these growth indices greatly varied with the different fruit species and also according to the salinity level used. As for the trunk cross - sectional area of the experimental seedlings, it significantly decreased with increasing the salinity level in grapevines, while it was not influenced in olive seedlings. In addition, total and top dry weights of olives irrigated with 2500 ppm NaCl salinity level was not greatly affected. On the contrary, the top to root dry weight ratio increased in grapevines grown under both salinity levels and in olive seedlings grown only under the highest salinity level (5000 ppm NaCl). 2. The growth rate, total leaf area and top, root and total dry weights of the two experimental fruit species were positively influenced by the The effect of the different nutritional, growth regulators and antitranspirant treatments as well as that of the NaCl salinity levels on the growth rate, total leaf area, stem cross- sectional area, total, top and root dry weights as well as top: root dry weight ratio was measured. In addition, the effect of the different treatments on leaf and root mineral composition (N, P,
Ca, Mg, Na, Cl, Fe, Mn and Zn), total, a and b leaf chlorophyll, leaf and root carbohydrate fractions (total carbohydrates, starch and reducing, non reducing and total soluble sugars), alpha total free amino acids as well as total phenolic compounds were also determined. The results of the present study, during both experimental seasons, could be summarized as follows:
Growth Indices: 1. Raising the salinity level of the irrigation solution from zero to either 2500 ppm or 5000 ppm NaCl caused a significant reduction in the seedling growth rate, total leaf area and top, root and total dry weights of grapevine and olive seedlings. The magnitude of reduction in these growth indices greatly varied with the different fruit species and also according to the salinity level used. As for the trunk cross - sectional area of the experimental seedlings, it significantly decreased with increasing the salinity level in grapevines, while it was not influenced in olive seedlings. In addition, total and top dry weights of olives irrigated with 2500 ppm NaCl salinity level was not greatly affected. On the contrary, the top to root dry weight ratio increased in grapevines grown under both salinity levels and in olive seedlings grown only under the highest salinity level (5000 ppm NaCl). 2. The growth rate, total leaf area and top, root and total dry weights of the two experimental fruit species were positively influenced by the application of nitrogen, phosphorus, potassium, gibberellic acid, paclobutrazol or paraffin oil antitranspirant treatments. Nevertheless, the trunk cross- sectional area was not affected by the different treatments except, the addition of nitrogen to olives and gibberellic acid to grapevines; as they positively influenced the trunk cross – sectional area. As for the top to root dry weight ratio, it was positively affected by the application of paraffin oil antitranspirant to grapevines and olives, nitrogen and phosphorus to olives and potassium to grapevines. 3. Significant positive interactions were generally noticed between both or either salinity level and nitrogen, phosphorus, potassium, gibberellic acid, paclobutrazol and anitranspirant treatments on most of the indices used for describing the growth of the seedlings in the two fruit species experimented herein. The only negative interactional reaction was noticed between salinity and paclobutrazol on the top to root dry weight ratio of olives. II. Leaf and Root Mineral Composition: 1. The influence of salinity on the concentration of the different nutrient elements was negative, in most cases, except for leaf and root sodium and chloride content, as they markedly increased with increasing the salinity level of the irrigation water. This general trend was noticed in grapevine and olive seedlings. 2. Most of the significant influences on nitrogen, phosphors potassium, gibberellic acid, paclobutrazol and paraffin oil antitranspirant treatments seemed to be positive on most of the determined mineral nutrients; except in only few cases, as on root zinc and manganese as the influence of these treatments was negative.