ASSESSMENT OF AIR POLLUTION TOLERANCE OF SELECTED TREES AND CROP SPECIES USING BIOCHEMICAL AND PHYSIOLOGICAL ANALYSES

This study investigated the air pollution tolerance of poplar (Liriodendron), eucalyptus (Camaldulensis), orange (Citrus aurantium) and sugarcane (Saccharum officinarum) present along Katlang Road in District Mardan, Pakistan with heavy vehicular traffic. The plant species were analyzed for ascorbic acid (AA) content, total chlorophyll (T. Chl.), relative water content (RWC), leaf extract pH, and air pollution tolerance index (APTI) was estimated from these parameters. The same plant species in adjacent sites away from the road were studied as control. Overall, all tree species had higher APTI values than the crop species (sugarcane) in the order as eucalyptus> poplar>orange> sugarcane with APTI ranging from the highest of 11.52 in eucalyptus to 8.24 in sugarcane. The study found that the sensitivity and tolerance in these species can be used as bio-indicator while the higher plants can serve as better sinks for air pollutants. The APTI determination technique proved as a reliable method to screen sensitive/tolerant plants under field conditions with deteriorated air quality.