AIR POLLUTION TOLERANCE INDEX (APTI) OF VARIOUS PLANT SPECIES GROWING IN QUETTA CITY, PAKISTAN
This study focuses on the determination of Air Pollution Tolerance Indices (APTI) from twelve plant species growing along polluted site (the road side of Quetta city) and non-polluted site (Botanical garden University of Balochistan, Quetta). The APTI was determined by synthesizing the four different physiological and biochemical parameters i.e. leaf relative water content (RWC), ascorbic acid content (AA), total leaf chlorophyll (TCh) and pH of leaf extract. The plant species selected for the study were Fraxinus xanthoxyloids, Robinia pseudoaccacia, Vitis vinifera, Pistacia atlantica, Rosa indica, Melia azadirachta, Punica granatum, Morus alba, M. nigra, Prunus armeniaca, Euclaptus terticornis and Ficus carica. Air Pollution Tolerance Index (APTI) was found higher in the plant samples of polluted sites compared to the non polluted sites. The results showed that decrease in total chlorophyll content was recorded in the leaf samples of all selected trees collected from polluted sites whereas the increased values were recorded in the leaf samples of non polluted sites. The maximum reduction (40.39%) of total chlorophyll content was recoded in the leaves of Prunus armeniaca and minimum reduction (4.48 %) was in the leaves of Morus alba of polluted site. There was maximum increament of relative water content (38.87%) in the leaves of Fraxinus xanthoxyloids and minimum increase (4.19%) was found in the leaves of Vitus vinifera of the polluted site. Ascorbic acid contents showed maximum value (39.13 %) in the leaves of Ficus carica and minimum amount (18.75 %) was recorded in the leaves of Vitis vinifera of the samples collected from polluted site. The maximum pH (6.85 ± 1.00) was observed in the leaves of Vitis vinifera and minimum value (5.44± 0.86) was observed in the leaves of Morus nigra of polluted site. The results were further statistically analyzed by using t-test showed significantly high level of pollution at the pollution sites, in all the parameters studied mainly due to automobile exhaust.