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Abstract
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ٍEffects of soil salinization were studied on seedling growth, proline and some macro-nutrient concentration in leaves of Ziziphus spina-christi (L.). Sodium chloride (NaCl) was added to the soil to maintain electric conductivity at1.8, 5.8, 10.2 and 16.2dSm-1. Seedlings were grown in pot under controlled greenhouse conditions. The experiment was designed according to randomized completely block design (R.C.B.D.) in a factorial experiment with two factors, i.e. four levels of NaCl (First factor) and two genotypes of Ziziphus spina-christi (Second factor) with four replicates for each experimental unit. After 10 months, the results showed a significant decrease in all studied vegetative characteristics (stem height, total leaves area, shoot fresh weight, shoot dry weight, root dry weight, chlorophyll index and number of leaves per plants) with increasing the salt concentrations. These reductions almost were predominance in genotype 2 than in genotype 1. Low levels of salinity (5.8dSm-1) did not cause substantial inhibition of growth but increasing concentrations of salt induced a progressive decline in vegetative characteristics. Potassium and phosphorus, content in seedling leaves significantly decreased as soil salinity increased but an opposite impact occurred with increasing the proline and Na concentrations. The proline also was significantly higher in the leaves of ‘genotype1’ than genotype2. The results imply the predominance of the genotype 1 in determining salt tolerance in comparison with genotype 2
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