Abstract
Physiological processes, photosynthesis, carbon and nitrogen metabolism, osmotic adjustment and secondary metabolites are known to be affected by air and soil pollutants. The present study was designed to evaluate the impact of air and soil pollution in Jeddah city, Saudi Arabia, on the physiological processes of Moringa oleifera. Four accessions differing in their pollution intensity were selected for this study (S1-S4). Elemental analysis revealed that Pd, Cu, Mn, Cr, Fe and Zn were the main soil pollutants in study accessions and trees growing in S2 have accumulated large quantities of these metals in their leaves. The physiological response to environmental pollution in M. oleifera tree was found to be dependent on pollution intensity. The heavily polluted accession showed a different response from the rest of accessions. As an adaptive strategy to environmental stress, this site has shown an increase in some metabolites such as lipids, flavonoids, free amino acids, alkaloids and saponins. However, some metabolites were decreased in response to pollution intensity such as soluble sugars and proteins, ascorbic acid, and terpenoids.