الفهرس 
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Abstract
Cairo, the capital of Egypt, is one of the most polluted cities all over the world. It is the busiest urban, commercial and industrial center in Africa and among the top 10 most crowded city in the world (CAIP, 2001). This associated with the hot and dry weather of the city will aggravate the problem of air pollution. The present work investigates the impact of air pollution on the morphology. anatomy and physiology of the leaves of two common tree species in Egypt: Eucalyptus camaldulensis (Dehnhardt.) and Ficus retusa (L.). Five different highly polluted sites were chosen in comparison with a control site (6th of October city); these sites are: iron and steel (site l ), cement (site 2), limestone (site 3), traffic (site 4) and smelters (site 5). Air pollution led to marked malformations in and reduced area of the leaves of both species; burning of blade tips, chlorosis and bending of blades are common symptoms. The internal structure of the leaf was also altered with reduced thickness of midvein and its vascular tissue. The thickness of collenchyma above and below the vascular tissue of the midvein was also altered. In addition, pollution had severe consequences on leaf metabolism. All the physiological traits estimated (photosynthetic pigments, sugar fractions, nitrogen fractions, phosphorus fractions and the mineral nutrient K) were severely reduced under the impact of air pollution, with pollutants emitted from sites involved in metallurgical processes (iron and steel and smelters) leading to the worst effect while pollutants from limestone quarries led to a mild effect. Pollutants accumulated in leaf tissues and on leaf surface to different extents according to the plant species and site of study (source of pollution). For the two species, the concentrations in leaf tissues of S and Ni were highest at site 4, of Fe and Cd, at site 1, of Zn, and Cu at site 5, of Mg at site 2. In general the contents of heavy metals in leaf tissues were highest at site 5, followed by site 4 and site 1 but least at site 3. The sites most contributing to emission of heavy metals were iron and steel (site 1) and smelters (site 5). Pollution imposed distinct alterations in protein expression in the leaves of both species. Novel bands appeared and some bands disappeared as a result of air pollution. The majority of novel bands were of low molecular weight. Some other bands were expressed to different extents under the impact of the different pollutants. The response of protein expression was correlated with the concentrations of heavy metals in leaf tissues and in leaf surface deposits.