Air pollution effects on the structure of Citrus aurantium leaves

The long-term air pollution effects on the structural features of the leaves of Citrus aurantium, a decorative species planted throughout Athens, Greece, are reported. Leaves from plants grown in heavily polluted sites of the city and from relatively clean areas were collected and analyzed. The effects of air pollution on chloroplasts seems to be detrimental. Plastids of leaves from polluted sites are more or less spherical or lobed and they contain only a few stroma thylakoids; chloroplasts of normal leaf mesophyll cells are lens-shaped and present a well-developed system of stroma and grana thylakoids.