Assessment of air pollution tolerance index of Murraya paniculata (L.) Jack in Kolkata metro city, West Bengal, India

Constant bursting of the city frontiers is taking a massive toll on natural vegetation, deteriorating thereby the purity of the clean air. Biomonitoring of airborne pollutants through creation of green belts has become the only alternative to provide natural filtering barrier. The present study was constructed to evaluate the air pollution tolerance index (APTI) of a commonly found evergreen plant species in Kolkata, Murraya paniculata, based on leaf attributes. PAHs accumulating ability of the plant species was also examined so as to establish the species' potential in monitoring of PAHs. M. paniculata was found to be tolerant (APTI: 19.78 +/- 1.20-31.12 +/- 0.72) towards air pollution with dust capturing potential between 0.85 +/- 0.04-2.26 +/- 0.02 mg cm-2. Correlation analysis unveiled the strong relationship of foliar dust with leaf ascorbic acid (r = 0.931), leaf extract pH (r = 0.985), leaf RWC (r = -0.822), total carotenoids (r = -0.862) and total chlorophyll (r = -0.76). APTI was found to be correlated positively to ascorbic acid and foliar pH and negatively to total chlorophyll and RWC. Changes in leaf surface micromorphology due to particulate pollution were also endorsed by SEM-EDX analysis. Findings revealed that Murraya paniculata has the tolerance and efficiency of trapping both lighter and heavier PAHs, proving its ability for biomonitoring of atmospheric pollution.